hi there , well i know how to do this in logic , so maybe its kinda similar ... Logic has an audio window ..This contains all the audio files that are not only in the multitrack session , but any u have added to this list for quick insertion into the multitrack session. Under file theres an option to convert to stereo wave .. So u can select a mono wav and convert it quite easily into stereo ...Have a look at protools , im sure theres something similar to this... anyway , hope that helps...
spider