In order to reflect your RPX tokens in NEO-GUI- you have to go to 'watch' tab and add 'hash script' provided by RPX during ICO. Leave it for few minutes and Lastly, restart wallet. Check 'Asset 'tab you should see your RPX tokens.
If you still not able to see then do a 'mint token' transaction to RPX script hash with zero NEO. It will throw an error but at last you will see your RPX under 'Asset' section.