Your suggestion sounds fine to me.
You could also say something like "I'm looking forward to working with you and your team."

Aber "looking forward to" impliziert, dass Du Dich auf etwas freust, was noch nicht eingetreten ist. Wenn Du schon Teil des Teams bist, weil Du die Stelle ja bereits angetreten hast, müsste es m.E. eher "I'm glad to be a part of your team" oder "I'm happy I am a part of your team" o.ä heißen. Mit "looking forward to" könnte man z.B. "working on many interesting projects (with the team)" o.ä. verknüpfen (wenn mit der Projektarbeit noch nicht begonnen wurde.
Oder sehe ich das zu eng, the kat?

Ich finde Dragon hat Recht.

"I'm glad to be a part of the/your team."

I just sort of assumed (oh dear, you knaow what happens when we assume... ) that Exberliner just got the job and hasn't really started yet - in which case, both my and Ex's suggestions are fine.

If s/he has already started, then you could still use looking forward, perhaps to "contributing to the team", or, like Dragon suggested, "working on interesting projects", etc.