Problem using bcprov-jdk15on-162 on JRE 1.6

I'm creating a project using bcprov-jdk15on-162, but it must run in
java 1.6 (I know). But when trying to register the provider, I get the
following message:

java.lang.SecurityException: JCE cannot authenticate the provider BC

Researching the problem, I found that previous versions of the
provider are signed by:

CN=JCE Code Signing CA,OU=Java Software Code Signing,O=Sun
Microsystems Inc,L=Palo Alto,ST=CA,C=US

Meanwhile, this new version is signed by both the previous one and:

CN=JCE Code Signing CA,OU=Java Software Code Signing,O=Oracle Corporation

I've already included the provider line in java.security and added the
new jar to java lib/ext but the issue persists.

I've also tried registering the provider dynamically like:

Security.addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider());

But no luck.

How do I solve this problem for JRE 1.6?

Thanks.