This is my first post, so please bear with me.
I have booked a bus class flight with SQ from SYD to FRA in June '09 using Virgin Atlantic points. At the time of booking, I was not sure whether I was going directly to Berlin, London or New York from FRA; it pans out that I need to go to London first.
As the ticket is issued and the seat allocated, I have been told by a couple of travel agents that even if I book a flight from FRA to LHR with a partner airline (it appears LH is one) on the same day with only a transit in FRA, it will be a separate ticket and therefore highly unlikely that my baggage can be checked through. They also implied that this would be up to the check-in staff.
It won't be using points and I will probably book on-line, although I would use an agent if I thought it would help. It will be an econ ticket.

Thanks for your help and sorry about the long-winded post.
Pierreg