1) after download Proxomitron, extract and run proxomitron.exe(the green icon).. If any pop-up come out from your firewall just allow it..
2) In Proxomitron main window, "Edit Filter" section, click "Headers", then a "HTTP Header Filters" window will come out..
3) In "HTTP Header Filters" window, scroll down and you will find there is 6 user-agent option.. Choose  any one of them by ticking at "OUT" section and then click "Apply", "Ok"..
4) Configure your BT client to use this proxy..
5) Launch Proxomitron log windows and then start your torrent task to see if it works..

Proxomitron was using port 8080 on default so if u're behind a router, forward port 8080..

there is 6 user-agent on the list.. pick one or edit one of them to become like this..

For me I will go for paw since the proxomitron makes my torrent client a bit lag...Duno why...Is it just me the one? Who has the same problem with me? So far so go with the combination of paw+bitlord...I am able to download all the stuff at 50-60kpbs...The sad thing is that i have 1M connection but can such speed..Most my friend get 100kbps for 1M connection...Till now still dont have any idea how come got such problems...