Watchguard SSL Certificate problems
Solution 1:
I actually was able to figure it out. The certificates did need to be imported into the Watchguard. What the issue with importation was was that the Watchguard could not validate the entire certificate path.
To solve this I went through the Trusted CA list on the device and exported all the Valicert and Godaddy certificates that were applicable. Then I re-imported them as CA certificates by selecting the Other radio button on the import dialog.
After that I was able to import our Godaddy certificate no problem.