You can create any kind, e.g. link.
You need the menuid, so you can use it as Itemid (it's the same) in the reg page url, and then use it again to choose the modules you want to have displayed on the registration page (using the menu in the list to show those modules).
This is why you need added &Itemid=XYZ to the registration page url, where XYZ is your menu id.
After having created the menu item, and assigned modules to that, and before hacking mod_cblogin, you can just add the &Itemid=XYZ to your registration page by editing the URL.
Or even wihtout changing anything, you could copy the &Itemid from a page that shows the login modules and add it to the registration url to see the modules appear.
I know the above is concentrated and will require a double-reading after some coffee, but that's how joomla works and what the Itemids are for (among other things, like breadcrumbs).
You may also browse joomla doc and forum for further explains on Itemid and menuid
EDIT: didn't add anything finally
wrong edit.
Post edited by: beat, at: 2008/07/26 23:45