Llook at this forum http://forums.m3cutters.co.uk/forumdisplay.php?f=75. Prior to seeing this I bought a lead and software from eBay and got it working but felt very vunerable as there wasnt any support.
I have purchased a copy of the BM Technic version of the software (same in essance as the others but a 'one click' install and a 'control centre' to load the software for use) and their cable http://bmtechnic.co.uk/ as they will support the installations and also (to a degree) support the use of the software. Especially with the 'How to' guides.
Loads of help and support from Chris at BM Technic
Good luck
Norman