Haneo,
I'm new here, so this may be too late for you, but you can actually do what you want on the PIX. Yizhar is correct for OSes before 6.0, but I see that you say you are 6.2, so this should work.
Try:
static (inside,outside) tcp x.x.x.x 80 10.10.10.10 8080 netmask 255.255.255.255 0 0
The x.x.x.x is any valid outside address (including the PIX outside interface address for PAT users)
Having said all that, I have never tried it between 2 'internal' interfaces, but I can't think of any reason it wouldn't work.
If you're only changing the port number and not the address, I'd suggest trying something like
static (inside,outside) tcp 10.10.10.10 80 10.10.10.10 8080 netmask 255.255.255.255 0 0
... but again, I've not tried that myself.
Hope that works for you,
PD.