Convert Physical -> Virtual address to set a break point on it

There is a physical address that I need to find its virtual mapping via
Windbg to set a break point on it. Softice has a PHYS command that does
that for you.
I have posted this question on another forum and I have yet to receive a
satisfactory answer. I was told that this is tricky and I could possibly
get it via !PTE.
Windbg details every step to produce a physical address from a virtual
address but nothing specific exists for physical -> virtual. Currently I
can view this memory location via !dd [uc] 98000000 which resides on an
AGP card.
Can anybody help.