I know a trick called waving the aces, but I'm not sure if it's the same one you're on about. Here's a quick description of the one I know.
The effect:
You take out two aces and give them to a spectator to hold or put them on the table. Then you have a card freely selected (and signed if you wish) and you put it back in the deck. Then you show the two aces once more, then wave them over the deck. "Magically" the selected card appears between the two aces in mid-air.
If this is the right trick then I may be able to help. There is the standard solution and there are two solutions I use for this depending on how confident I'm feeling:
First of all, the sleight can be done whilst they are signing a card. In most cases this will give plenty of misdirection. However, in some cases this won't work. Either because you aren't having the card signed (which I really think you should), or other people around you are paying too much attention to what you are doing and can spot the move whilst the speccie signs the card.
Secondly, you can choose to perform the sleight near your leg (as standard) but with only one hand. I find this to be really effective when you can do it well (takes a little practice to do it without the hand looking awkward). This way you can do it whilst misdirecting them as they give you the card back. You can be talking about their card ("it's signed, personalised, the only one like it in the world, bla, bla bla") and do the sleight by your leg one handed.
Thirdly, just use a different method of keeping the card on the top (Mods: can I say that? Don't wanna expose anything!). One which I feel works pretty well in this situation is the "James-Ellis Load-on" which can be found on Ellusionists "Crash Course 2". I think this is better than the method you're talking about as no misdirection is required AT ALL.
Having said all of this, we might be on about two completely different tricks. Hope this helps. If I can assist anymore, please...just ask.