Partner Center Hardware Program Registration

Question

I'm trying to register for the Hardware Program in the Partner Center.

When uploading a signed testfile I always get the following error:

We encountered a problem processing the file you uploaded. Please ensure the file you sign and upload is the same file you downloaded.
Correlation ID ......

I am sure I use the correct, previously downloaded file and it is correctly signed.

Unfortunately, there is absolutely no help or guidance to these error messages - which is very bad customer support. No help, no guidance, no contact option ... this actually is a no-go IMHO.

I need to get this solved because I need to submit drivers for WHQL certification.

Thanks

Franz