Did you get anywhere with this? I've successfully created an SSL certificate with a SAN but HPSIM refuses to honor it, returning the following error:
The hostname in the website’s security certificate differs from the website you are trying to visit.
Error Code: DLG_FLAGS_SEC_CERT_CN_INVALID
I've tried all sorts of combinations of certificate generation but have been unable to get it to work. If I remove the SAN everything is OK.