I too, have this problem. It also seems to cause problems with the Impulse overlay as it sometimes doesn't appear or refuses to disappear.

I launch it through steam, Impulse isn't active, I can't find any process related to impulse either.

Yeah, maybe there are some launch options I'm not aware of.

I found if I re-bound the steam overlay trigger to something other than shift + tab I could get it to open up the overlay, unfortunately I can then only do mouse driven tasks which cuts down a lot of functionality...  

I'm going to test it with a friend sometime soon and hopefully we can get voice chat working.

Happy to report that x-fire works without trouble, so there is 'some' hope of getting steam to work, however I suspect that stardock is actively opposed to us using it given that it's the established competition.

Hopefully after impulse gets itself a user base and sorts out its many many issues they can approach steam and x-fire to talk about a standard gaming portal communication mechanism (like how the IM clients eventually got federation) and then we can use our impulse client to talk to our steam buddies and vice versa.