[MapProxy] Configure external wms that requires basic auth

[karsten]

Hi All, 

I would like to configure a cache for a third party wms that requires basic
auth for example in the format:

http://12346puser78:98pw65432@www.geodatenserver.net/ogc/ogc_layers.cgi?

What is the best way to configure this with MapProxy ? So far I simply tried
to use the above url in the url parameter of a wms type aye which did not
work 

Karsten