It would seem to me that if you already use UCA then you already have the ability to dial out via outlook. To be specific, just one of the many ways I do it is go to the contact in outlook, right-click, and select "Call Contact."
Another box opens up and I then select "Start Call" which kicks UCA into dialing the number in question. It's nice because if you have more than one number associated with a contact, you can choose whether you are dialing the desktop or cell phone or home phone.
I'm running Win7 64 at home and will have to test dialing out there, as I have UCA running on my home PC, but I fully anticipate it working.
There was no specific outlook plug in that I was aware of in the UCA install. It is very Outlook aware. I have no experience with UCX. I believe, however, they are extremely closely related.