i tried and you can't because its enclosed.
Dude, sorry to hear of your mis-fortune but i'm wondering which MBP is it? And do you think you have the necessary skills to dissemble the entire unit to get something out, without causing
any damages to the other innards? My thinking (now I ain't see the back of Apple's sockets, well, not on those new unibodies, but, if it's a mini jack socket, the other end should be open, unless it's a combined unit with the built-in optical digital out, in-which case, your only option is to de-solder the socket from the logicboard carefully and void any warranty that might be on the machine forever!! Then continue to dissemble the socket, the RF shielding should be clipped together.
It's a lengthy process, not something anyone should be doing without electronics experience, you can after all kill the machine, completely!!! One need to ask themselves is it worthwhile???
Alternatively if you really need to use the mini-jack for headphones, there's a USB alternative but it's no substitute for the built-in's.