Choice of HQs in skirmish : bug or feature ?

Hi,

I have OTC with Jupiter expansion (not a choice, it was pre-pacakaged like this) and when I start a skirmish mode, I can't access to the HQ I want, it gives me 4 random HQs out of 6.

Is there a way to choose among all the 6 types of HQs ? Otherwise, is there a way to disable the Jupiter expansion to get only the 4 basic HQs ?