Mobile subdomain: problem with current htaccess settings pointing every subdomain to one version

Hi,

I have a problem with my htaccess and hope someone can help me. I have a project with some domain aliases: the project is found under "www.my-site.de", but there are aliases like "mysite.de" or "my-site.at". To assure that every domain alias with or without leading "www" is redirected to one domain version ("www.my-site.de") I use the following setting in my htaccess:

RewriteCond %{HTTP_HOST} !^www\.my-domain\.de$
RewriteRule ^(.*)$ http://www.my-domain.de/$1 [L,R=301]

But: this redirects "m.my-site.de" - the wanted mobile subdomain - to "www.my-site.de" as well. Unfortunately I am not very familiar with regular expressions and htaccess so I want to ask here in this forum if someone can tell me how I could change these settings in order to assure that my project keeps being available under one domain except for the mobile subdomain.

Best,
Tobias