I am able to play Hummy .ts files over wifi on a PlayOn HD media player I have in an upstairs bedroom (similar capabilities to the WDTV Live).
You should be able to achieve this on the WDTV Live using two methods:
Windows networking: You will need to use the custom firmware package to decrypt the files (custom firmware can be set up to do this automatically) and install the samba package from the custom firmware. You should then be able to browse to your Humax video folder on your network with the WDTV Live.
or
uPnP: Turn on Content Share on the Humax (not necessary for samba). No need to decrypt files. Browse to your file via uPnP.
Personally, I find samba is faster but that might just be the vagaries of my network.