Yes mate .. just done mine follow the instructions below..
You need to decert the phone first, before it can be unlocked. This will allow you to get into the phone to change the lock this can be done in 2 ways (the developer site is the simplest but takes 24hrs)
This can be done using the attached registry editor (PHM regedit signed with the trusted HTC certificate).
3. OK with that out of the way its easy, you will need to have microsoft activesync so you can link the spv c500/C550/c600 to your computer (you can get this from the microsoft site) and a usb cable you get with the phone, its a standard usb connection
4. Open activesync with the handset connected and hopefully the software will detect the phone, now use the explore button and go to where you saved the files, copy the cab file to the phone (i copied to storage/windows/startmenu/ accessories you need only copy this file to the phone).
Now when you goto this location in the phone you see the cert.cab file there, all you do is run this from the phone.
After it has installed this you need to power off the phone, power on again and run the spvservices.exe from your PC with the phone still attached to the usb cable and it will take you to the spv-developers site where you will be able to unlock the phone. I ran both the SIMLock Tool and the CID Tool and its sorted! to check it worked just download the checklock.exe onto your phone (as before) and run it, this will tell you that its either locked or unlocked.