hey jax,
sounds like there was some confusion but I'll try to get this sorted

what sam actually meant is that there is a default url format for profile links, in fact there are 2 formats you can choose from:
1) id-username or 2)id-realname

both are working absolutely fine, there's no need for sh404sef at all to generate these links. additionally you can use a permalink field, this gives you the possibility to change the url to whatever you want it to look like and this also doesn't require sh404sef as well. this is a field that is provided by easysocial and you can use this without any other sef extension involved.

hope that clarifies things but if you have any more questions feel free to get back to us at any time. have a nice day