I think Comoman was responding to the OP's statement that they'd previously booked codeshares through VA (which would have had a VA flight #) but is looking at booking directly with SQ on this occasion, which of course means no eligible sectors as they would be SQ flight numbers.
We've just done something similar with our upcoming trip to Europe i.e. booked directly with SQ this time as the fares were cheaper and we were able to do seat selection, purchase exit seats etc without any issues - this trip won't accrue enough SCs to requalify either of us for Gold anyway, so as we're going to have to do a few domestic flights anyway to pick up the necessary SCs, we'll get the eligible sectors from those.
We've just done something similar with our upcoming trip to Europe i.e. booked directly with SQ this time as the fares were cheaper and we were able to do seat selection, purchase exit seats etc without any issues - this trip won't accrue enough SCs to requalify either of us for Gold anyway, so as we're going to have to do a few domestic flights anyway to pick up the necessary SCs, we'll get the eligible sectors from those.