There is no 1.1. You must be referring to the PDF document that says "NeroCOM v1.1". It indeed has no information on VMS as it seems to be not quite up-to-date.
There is a MediumFlags property on NeroCDInfo object. You should see if flag NCDIMF_VIRTUALMULTISESSION is set. If so, you can use GetVMSInfo() method on NeroDrive object. This will give you a NeroVMSInfo object which you can query for VMS sessions. If you now want to import a VMS session, you should call ImportIsoTrack() on a NeroDrive but be sure to include NERO_IMPORT_VMS_SESSION flag as TrackNumber will then be interpreted as a VMS session.
The rest is same as always...
I am not familiar with Borland C++ Builder, but you should be able to get more details from some form of "Object Inspector".