getting an exception when trying to initialize ApnsServiceBuilder

I need a .p12 file in order to authenticate with Apple's notification servers, and I have found some problems. As I understand, I need to generate the .csr and my private key identifying my machine. So I need to execute a command like this in my local machine:

*$:~/Escritorio/curro/certificados$ openssl req -out CSR.csr -new -newkey rsa:2048 -nodes -keyout privateKey.key
Generating a 2048 bit RSA private key

writing new private key to 'privateKey.key'

Now, with my CSR.csr file, I need to login in to:

https://developer.apple.com/account/ios/certificate/certificateCreate.action?formID=62653259

then I provide the .csr file generated before and the system gives me a .cer file (aps_development.cer) . Now, with this .cer file I have to generate it .p12 equivalent file. In order to do that, I need to make a .pem file starting from that .cer generated file from Apple. This is the command:

@Ubuntu:~/Escritorio/curro/certificados$ openssl pkcs12 -export -inkey privateKey.key -in developer_identity.pem -out iphone_dev.p12
Enter Export Password:
Verifying
Enter Export Password:

After that I have a .p12 file and I need to initialize an ApnsService instance,

@Component
public class NotificationServer implements Runnable, BeanFactoryAware {

@Autowired
// APNS channel
private ApnsService serviceApns;
private String apns_payload;

@PostConstruct
public void init() {
// build apns service path_to_apns_certificate, absolute path .p12 file 
String path_to_apns_certificate = config.getProperty("a-path");
//pass used to generate the .p12 file       
String password_apns_cert = config.getProperty("a-path");
log.debug("path_to_apns_certificate: " + path_to_apns_certificate);
//keep an eye with this!, this builder is non thread safe!
ApnsServiceBuilder apnsbuilder = new ApnsServiceBuilder();

String sMaxConections = config.getProperty("maxConections");
log.debug("sMaxConections: " + sMaxConections);
int maxConections = Integer.parseInt(sMaxConections);
apnsbuilder.asPool(maxConections );
String connectWithAppleApns = config.getProperty("apns.production");
log.debug("connectWithAppleApns: " + connectWithAppleApns);
apnsbuilder.withAppleDestination(new Boolean(connectWithAppleApns));
//here the exception is launched!       
apnsbuilder.withCert(path_to_apns_certificate, password_apns_cert);
serviceApns =apnsbuilder.build();       
}
}

Here is the error message:

Caused by: com.notnoop.exceptions.InvalidSSLConfig: java.io.IOException: failed to decrypt safe contents entry: javax.crypto.BadPaddingException: Given final block not properly padded
    at com.notnoop.apns.internal.Utilities.newSSLContext(Utilities.java:88)
    at com.notnoop.apns.ApnsServiceBuilder.withCert(ApnsServiceBuilder.java:167)
    at com.notnoop.apns.ApnsServiceBuilder.withCert(ApnsServiceBuilder.java:134)
    at com.*****.agenda.utils.NotificationServer.init(NotificationServer.java:122)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor$LifecycleElement.invoke(InitDestroyAnnotationBeanPostProcessor.java:346)
    at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor$LifecycleMetadata.invokeInitMethods(InitDestroyAnnotationBeanPostProcessor.java:299)
    at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor.postProcessBeforeInitialization(InitDestroyAnnotationBeanPostProcessor.java:132)
    ... 164 more
Caused by: java.io.IOException: failed to decrypt safe contents entry: javax.crypto.BadPaddingException: Given final block not properly padded
    at sun.security.pkcs12.PKCS12KeyStore.engineLoad(PKCS12KeyStore.java:1304)
    at java.security.KeyStore.load(KeyStore.java:1214)
    at com.notnoop.apns.internal.Utilities.newSSLContext(Utilities.java:85)
    ... 174 more
Caused by: javax.crypto.BadPaddingException: Given final block not properly padded
    at com.sun.crypto.provider.CipherCore.doFinal(CipherCore.java:811)
    at com.sun.crypto.provider.CipherCore.doFinal(CipherCore.java:676)
    at com.sun.crypto.provider.PKCS12PBECipherCore.implDoFinal(PKCS12PBECipherCore.java:355)
    at com.sun.crypto.provider.PKCS12PBECipherCore$PBEWithSHA1AndRC2_40.engineDoFinal(PKCS12PBECipherCore.java:462)
    at javax.crypto.Cipher.doFinal(Cipher.java:2087)
    at sun.security.pkcs12.PKCS12KeyStore.engineLoad(PKCS12KeyStore.java:1295)
    ... 176 more

Can anyone give my any perspective on this?