Making a footswitch for a v-panel varies slightly from the design of the i-station footswitch application See attached .pdf for a better view of this design.
Download either of the attached documents: v-panel footswitch  Adobe Reader .PDF document or the Microsoft Word .DOC document.
Also refer to the notes in the V-seriesmanual in section 4-10 for more information. 
See DB-25 pinouts in the attached pdf / doc document 
General wiring and configuration directions are below :   
Get a DB-25 Male connector ......(The V-panel has a DB-25 female connector) - Jump pins 9 and 10 together.
- Connect pins 21 and 22 to the two legs ( + & -) of the switch.
In ECS, - highlight the port with the V-Panel you wish tocontrol with the footswitch,- in the LOGIC INPUTS category, change the LOGICINPUT 1’s function from “NO FUNCTION” to  “PTT: Activate all Talk keys”.
Apply the changes from ECS to the matrix.  Now, on the V-Panel, activate all Talk keysyou’d like to be speaking on. When you push down on the footswitch, the MIC ONlight will come on, activating the microphone. When not pressed, even thoughthe Talk paths are open, the mic is not passing audio. It will only pass themic’s audio when the footswitch is engaged.
* note other functions can be assigned to the footswitch operationlike toggle microphone , activate 2-way radio keys , activate key 1 or key 2 on the panel , activate any configured system control or route