I'm not sure if you've found an answer to your question but the answer is yes. I haven't done it personally but found this information in passing.
For info on how to create the custom MySQL provider check out:
http://www.codeproject.com/aspnet/My...ipProvider.asp
For info on how to add custom fields to your CreateUserWizard check out towards the bottom:
http://msdn2.microsoft.com/en-us/lib...serwizard.aspx
The magic is done in this section of Web.config:
<configuration>
<system.web>
<profile>
<properties>
<add name="lastName" />
<add name="firstName" />
</properties>
</profile>
</system.web>
</configuration>
Hope this helps if you haven't already found a solution.
Take Care