Windows 7: - the Mortar in BF3.. (??)

one thing that really peeves me about BF3 (apart from the totally unbalanced gameplay) is the mortar..

Ok, so I can equip it as a support soldier, I can even deploy it and cause havoc (great stuff!)..

- but, er...
- I haven't figured out how to "un-deploy" the blasted thing..

If I try to use any other weapon, after deploying the mortar, i simply can't select it
- I don't see any way to "un-deploy" the mortar..!!

- at the moment, all I can do is keep lobbing rounds onto the enemy - I can't move the mortar to another position..
- I have to wait to be shot by the enemy before I can re-arm with another weapon..!!


- can anybody help?
- have I assigned a key wrongly or what..!!?