Okay, sorry everybody, i been a bit busy with some other things. But i just got around to posting on HTC's website forums to see what this port is, and also i just got off the phone with HTC and the guy told me he thinks the port IS in fact for an external antenna to be added. And the technical name for the port is an FME.
Ive never heard of that, so im gonna do some research right meow.
Be back later with research results. And then if i find out what i need im gonna buy an external antenna that i can fashion to this device. And hopefully be able to hide it beneath the battery cover backplate.