One way I could think of is to produce the result slips for your 3 years in UOL, and then inform your prospective employer that the degree certificate is on the way.
Most employers do not mind waiting for the certificate as I guess they probably understand it would not be produced ASAP. I had colleagues who interviewed, got the job and their certificate was still stuck somewhere at the university. As long as you give the assurance that you will submit the certificate to HR once you received it, I do not see anything wrong.