Real helix server: Correct protocol for Windows Media WMV: UDP or TCP?

Please can some one help me?
I work for a large educational institution; we are currently testing our video streams on a Real helix server.
This content should me made available inside the network and to clients connecting externally.
Currently we are using Real and Windows streams. When I look at the WMV stats it appears the streams are being delivered via HTTP. Should they not be delivered using either UDP or TCP protocols? If so how do we ensure the streams are delivered using the correct protocol?
Many thanks.