if you have the manual and the valet code & the master remote you would be able to do it yourself.
It involves pressing the little 2 button pad you should have in the car (valet switch) in a certain fashion to increase sensativity etc.
The wizard port plugs into a little peice of loom what comes out of the alarm box. Then into an extention with the serial adapter on the end, you can find it on ebay usually these days, but most peices of software are a customer version so some features are disabled (but not mentioned in the auction )
Remote start is easy enough to install your self, all it is is 2 relays connected to the imobilisation circuits and then it uses a channel from the alarm which must be set in the cliffnet wizard tool.
Or just take it somewhere to do it
As for the proxy. it depends if it came with the alarm then its controlled via the alarm, if it was fitted after it might have the adjusting screw on there