SinkWriter and MPEG2 TS

Is there anything specific that needs to be done to the SinkWriter to configure it to write MPEG2 Transport Stream?

In an effort to write a TS segmenter I'm getting MF_E_INVALIDMEDIATYPE on WriteSample. The MFCopy sample exhibits the same behavior.  

H.264/AAC compressed samples are coming from another TS file through the SourceReader. The end goal would be to locate the IDR boundaries and start a new file when one is detected. No transcoding, just a simple remux from TS to TS.

Any advice would be much appreciated. Thanks.