How to rewrite slugs into subdomains

Does anybody know how to map custom subdomains to specific URLs?

Let’s say I have a page called “My page”, which has some child pages. I’d like to rewrite the URLs so they would work like this:

mydomain.com/my-page/ --> my-page.mydomain.com
mydomain.com/my-page/child-page/ --> my-page.mydomain.com/child-page

Same thing goes for custom taxonomies:

mydomain.com/taxonomy/my-taxonomy/ --> my-taxonomy.mydomain.com
mydomain.com/taxonomy/my-taxonomy/child-taxonomy --> my-taxonomy.mydomain.com/child-taxonomy/

I found the WP Subdomains plugin, which does exactly what I need, but it won’t work in WP 3.x.

Thanks in advance for any help you may give me.