How about "Custom URL:" but before the text field for input, the base URL is presented as a static text? This implies that what is to be input is the bit after the base URL.
I am not sure the current form API allows this, but it sounds good too.
I don't also think it alows this... I don't know how to make this. Btw, I'm sorry Morbus, but I don't understand your complaint, the help below the field text made it pretty clear that you just need to add the final path doesn't it ? See : Specify an alternative path by which this data can be accessed. For example, enter mypages/about if you want a page to appear at http://192.168.0.180:8080/drupal_cvs/mypages/about. This is my help text... I perfectly agree that URL maybe a little inapropriate as it describe "full URL" but how many time CMS or people use "custom URL" ? Regards tostinni