There's a bug, it's known about, it's in the bug tracker, but it's regarded as low priority in the run-up to open beta launch. Basically the site pages have some CSS and it conflicts with yours, so your codes aren't working on the userinfo page. So at the moment there are some restrictions in practice, but they're accidental and will probably go away eventually. (I think you won't be completely free to customize your userinfo page, because it needs to show all the information that the site expects, but I'm not sure DW is going to be keeping that restriction forever.) Once the bug is fixed anything that works on LJ should work here, anyway.