A21

It's a little bit fuzzy because of the dual keywords on Hexblade powers (which is really what you're talking about, right?), but the answer would be that you are "holding" your implement (i.e. your bastard sword) in one hand and "wielding" your Pact Weapon (whatever the appropriate variety is) in your other hand. But if you had a Weapon power that attacked with separate attacks from both hands, it would be a problem.