This link is courtesy of CCA4 - it's his procedure, written up for AudiFreaks.com, and he's allowed us to include it here on AF. As usual, if you set your car on fire or it catches gonorrhea from following this, well, you're dealing with Chris so you take your chances

Anyhow, here's the DIY. Many of us followed it for our conversions and it'll get you through, no problem.

2-Piece to 1-Piece Headlight Conversion - AudiFreaks