"Append these dns suffixes (in order):" grayed out

[Guest]

Windows Vista Home Premium

I'm setting up a VPN connection to work but I can't enter the necessary DNS
suffixes.
When I click on the TCP/IP > Properties > Advanced > DNS, the middle part of
the screen has the "Append primary and connection specific DNS suffixes"
selected but grayed out.
It also has the "Append parent suffixes of the primary DNS suffix: checked
and grayed out.
The other radio button "Append these dns suffixes (in order):" is not select
and grayed out.

I need to selected the "Append these dns suffixes (in order):" so I can add
my DNS names.

Why can't I select it?
Thanks,

 

[Guest]

I've got the same exact issue with Vista Business edition. I need to get
this to work for our VPN clients. I've done a web search multiple times but
have come up empty handed.

How can I change the DNS Suffixes for a VPN connection when they're grayed
out?