Hello Simon,
If you mean.
Site 1 -> Customer
Cloud Site -> You
Client traffic
Site 1 -> Cloudsite -> internet
Nope this could not be done in 4.2 2 was told by Citrix, 4 month ago...
if you mean,:
Client traffic
Site 1 -> Cloudsite
Site 1 -> internet
This works.... 
Kind regads
Gert





