This problem exists because the brain-dead programmers at Citrix don't use the Mac's Keychain for storing certificates. The Network Solutions certificate is built into Mac OS X, but the knuckle-dragging mouth-breathers laughingly referred to as "programmers" over at Citrix don't know that.
For what it's worth,
this page describes how to copy the Network Solutions certificate out of the Keychain and into the Citrix certificate repository.
