HTML Code Reverting Back To BB Code

[Narutoboy]

I created some internal links within a thread so that users can navigate to specific headlines within the FAQ. To do so, I added an "a id" to the links and headlines. The problem now is, everytime I go and edit the thread, the code removes the HTML (e.g. <a href="#link1"></a>) and replaces it with the BB Code equivalent, which stops it from working. Can anyone tell me how I can stop this from happening? I have allowed HTML across the whole forum, by the way.