Baertracks

I am trying to book a rather complicated multi-city trip that includes 8 segments and three continents. I've given up trying to find that itinerary using .bomb. Web Support was useless, quoting me a fare of more than $6,000. Kayak.com couldn't put together all of the segments that I needed. However, I finally found what I was looking for at Vayama.com.

The entire ticket is labeled as being purchased from UA with all segments of the proposed ticket are in "V" Fare Code. "V" is OK for upgrading from economy to business, correct?

The flight from IAD-BRU is on UA 950 (UA metal) and is listed as such in the ticket. So that should not be a problem to upgrade using a SWU (space-permitting, of course).

However, the return home (FRA-IAD) is listed as being flight LH*9050 (* Operated by United Airlines). That means that it is the UA 917 metal flight.

So, since it is a UA metal flight and the ticket is being purchased from UA will I be able to upgrade using my UA SWU (space permitting) even though the ticket lists a LH flight number? If not, might I be able to use a paper SWU? Or, must I keep digging to find a ticket that lists this as a UA flight 917 on the ticket?

Thanks!