External Links and Default Values

Hi,
i seem to have misunderstood a lot what the link module does or doesn't ...

My scenario:
I have a content profile page, where user are asked for their nickname in an older site of ours and make it linked to their profile page on that still existing page.

As i do not want them to have to put in the hole url, i thought i could help them by already giving the beginning of the url as default value, which the users then simply had to complete by adding their nick.

http://myoldsite.com/member/

Unfortunately, the "default value" for the url nor the title simply do not show up in the form, the fields are just empty.

So, can someone explain to me what i have done or expected wrong?

Or what other way can i go to prepopulate that link field with http://myoldsite.com/member/ ?

Thanx a lot
Bernd