Retrofit electric windows

[PartnerHDI]

Hi, I want to fit electric front windows to my 06 Partner van. I have the switch connectors behind the dash panel and I have activated the window function in the BSI but don`t have any power up to the switches.
Has anyone tried retrofitting elec windows? Does anyone know if I need anymore loom wiring or where the switches feed from?
Any help much appreciated before I give up and wire them in the old fashioned way.
(I did do a seach first this time, but with no luck)

[ST12AT]

This is something I've always wanted to do (along with air con but that seems to involve far too much effort).

What did you do to get as far as you have got? List of parts would be great?