If you allow anonymous access to the document, the user will be anonymous (from QVS perspective) and hence you cannot utilize User CAL:s. Section Access is performed after authentication/handing out CAL:s and has nothing to do with authentication per say.
If you use Custom Users, a CAL will be handed out based on the customer user as can been see on the assigned CAL tab. If you want to utilize Section access for this custom user, try adding the user into the field NTNAME in section access, like:
Load * INLINE [
CUST1, ADMIN ];
See if that helps.