gdb with tramp problem

[Joe Bloggs <who@cares.invalid>]

When I load a remote c file with tramp, and run gdb through emacs on the 
corresponding executable, tramp runs gdb on the remote machine as required. 
However when I set a breakpoint and try stepping through the code, it fails
to indicate the current position in the buffer containing the remote source 
(as it would if I ran gdb locally with a local source file). Instead it opens 
a new empty buffer, and gives it the same name as the remote source file, 
and with a local path (e.g. instead of /me@remote:/home/me/file.c
it's listed as /home/me/file.c).
Can anyone tell me how to fix this?