(ALL JABRA DISCONTINUED!)
Yes!
You can plug your Jabra corded headset into the Executive Pro amp using the 8800-01 quick disconnect cord (Catalog # 9128). Plug your Jabra + QD cord into the headset jack of the amp and then use the connector cord that came with the amp to plug into the phone.
It should work on the same compat settings as EP headsets (1 and A).
Huzzah!