Hi All!
Thanks for the comments!
The mortar can only be fired when stationary, the idea is fire it at your objective and then charge it and over run it all hopefully while it's still stunned by the mortar shell striking it
the mortar can only be reloaded from outside the vehicle and in my FUBAR VSF skirmish games I doubt that will ever occur as it would take to long to set up the crane prepare the powder and shot and load it up...
Rich H do you mean set up some 'legs' that can be extended to stabilise the trailer while firing?
Glad to see this may give others some ideas for their own projects!