I'd like to have wildcard dns on my domain (shared IP) so that non existing subdomains all point to my main domain, and existing subdomains still work properly.

I've added *.mydomain.com to the ServerAlias of my domain, but now even my existing subdomains point to my main domain, which isn't right.

Anyone with an idea how to solve my problem? Example would be great :)
thx.

Move the VirtualHost block for your domain below the VirtualHost blocks for your sub-domains.

I believe if you set the subdomains above the wildcard in the zone file it'll work in that order. Atleast, it has for me.