[Hampshire] Search domains in resolv.conf

A pet peev of mine I was hoping you might be able to help me with!
I connect to our company network over standard ethernet Lan, using DHCP
- however I need to add in an extra 'Search domain' to resolve some
internal website addresses.
This works fine for a single session by adding 'search blah.com' into
the top line of /etc/resolv.conf or via the networkmanager gui; however
as soon as I restart, it overwrites the information and I lose my search
domain.

I'm running Ubuntu Feisty, though I'm sure fedora did the same - any
ideas how I can get this configuration to stick?

Thanks,
Charlie*
*