To get 506th in the launcher, you need to join the unit
here On the
My Units page, you can leave your old unit. I believe you can also leave units from the launcher directly.
To get the XML, you need to submit to
this thread (see spoiler tag for post format) to make sure you're in the XML (you're not currently), and then configure your profile to include the URL (
http://www.dtclan.co.uk/squads/28725093/squad.xml). For help configuring your profile, see
here.
In-Game: PV2 K.Knight
Name: K. Knight
Billet: Infantryman, 2nd Platoon, Alpha Company
PID: 76561198046702731
For more details, see the PM you got when your recruitment application was accepted - it's all in there.