Vulnerability Development: AlphaNumeric Exploitation Help

[<ramatkal () hotmail com>]

I am trying to exploit a vulnerable server which only allows
alphanumeric characters....

I have successfully taken control of EIP and now need to do a JUMP -600
bytes.....

The problem is, that 'eb' and 'e9' are not alphanumeric asci codes and 
thus cannot be used to do the jumps in the payload....

Anyone got any ideas/tricks/advice on how i can accomplish a JMP -600 bytes, or any type of jump for that matter, only 
using alphanumeric chars?

Thanks,
RaMatkal