DTDs, XML, tpegML, XSDs & C#

Hi all, this is my first post here and I'm just getting in to c# for a number of reasons.... although I have a bit of html, php and a tiny bit of java skill VS 2005 and C are completly new to me....

Any way - I'm currently looking at writing a programe that takes a tpegML ( and eventually DATEXII ) feeds and provide a user interface for a user to view them.

The feeds them selves ( eg http://www.bbc.co.uk/travelnews/tpeg/en/local/rtm/rtm_tpeg.xml ) although they have a xml name do not want to be imported as a data source in to VS as they dont meet WC3 criteria ( so VS says ). On further investigation I believe this is down to the refernce of DTDs within the feeds them selfs ( example dtds )

I've tried converting these dtds to xsds ( I working on the basis this is part of the problem ) but again these dont seem to meet the expected spec.

Can any one offer any advice or help on this ?

Thanks

Terran