Sure, no problem.
When the EHS adapter worked, it was easy to set up, using the guided menu setup on the Jabra's touch-screen. The Jabra setup asks if you have an EHS adapter, and if so, which kind (answer = Generic DSHG). The Jabra device then performs the automated setup, including calling a test number and calibrating its settings. After setup, depending on how you have chosen to configure the headset, picking it up off of the charging cradle will take the OBi phone off-hook, ready to call on the default SP you have chosen on your OBi phone. If you want to call out on a different SP line, just press the appropriate line key.
Inbound calls can be answered remotely, by tapping the button on the headset. There is no need to press a button on the telephone.
Without the EHS adapter, the Jabra's guided setup also works, with the difference being that you say "no" to the EHS question, and then you need to press the headset key on the phone to go off-hook. Everything else specific to the headset works either way. You can't, of course, answer a call remotely (in another room), because you need to press the headset key to answer the call and send it to the headset instead of either the speaker or handset.
The OBi phone's settings related to the headset are in a very non-intuitive place. I expected to see them in the "IP Phone" section of OBiTALK Expert, but instead, they're in the User Settings --> User Preferences section.
See my screenshot below. Note that I now have EHS disabled, since my pre-release cable no longer works with the latest phone firmware.
BTW, Jabra recently updated the headset's firmware, so visit their support site to keep up to date.
It's amazing to reflect on how far technology has come, with automated, touch-screen/microprocessor-controlled, encrypted, wireless headsets available to the public, not just in a Star Trek movie. I'm typing this next to my 1947 Western Electric Model 302 rotary phone; imagine what Alexander Graham Bell would think about today's technology.