Maybe by getting a new case for either your phone or Wave you could find a place to keep the batteries without adding another pouch, if you are going for descrete. Something like this , for example from Nite-Ize. I've never seen this product in person, however, and it looks like it might be a little bulky. I don't know of one, but maybe someone makes something along this line for a leatherman.

FWIW,
Chris.