WIFI Access

Hi ya. I have just installed PBXinaflash, and am feeling my way around. So far, so good.
I was wondering if this can be used with my iPaq PDA and softpone app to connect to my PBX server/SPA3102 adapter via wifi to make calls that would use my wired line? Sounds like it should be simple, but I’m as thick as a whale omelet!
Also, I am not using the WAN router part of the SPA3102, because I need the VPN router that I have. I suppose I will need to port forward and punch holes in the firewall to make this happen. Well, I’m sure I’m not the only one to try this, so any help would be groovy.