How to use "?" when adding urls

I'm trying to add a url to configure ddns.

Whenever i try to add the ddns-http method and enter the following command:

Router(DDNS-HTTP)# add http://user: snipped-for-privacy@members.dyndns.org/nic/update?system...

immediately after "update" when i hit the "?" key i get: WORD

In other words, a listing of the acceptable parameters...

Can someone tell me how to enter a complete URL with the "?".

Thanks!