I've the same problem. My customer has an uc320 with two fixed fxo lines and two lines for mobile. The only way i've found to select the fxo line for mobile calls is by sharing the fxo.
But this is not the solution,
Cisco, dont you have any way (keying number 6, for example,..) for selecting an output fxo line. Can you modify the firmware to allow the uc320 to select the fxo line for doing a mobile to mobile call.
Please, we need a solution !!!
My customer is getting very very very ... better not to say
Waiting for hear from you soon