The easiest way to do that now is:
* click on the texture tag to show it’s parameters in the Attributes Manager;
* Ctrl + click on the small dot to the left of the word “Material”;
* move the timeslider forward and drag the second material from the Material Manager into the link box next to the word “Material” (above);
* Ctrl + click the small dot again.
That’s it. Now when you render Cinema will blend between the two materials.
If you drag the texture tag into the timeline you’ll see the track that was created–in case you want to do it manually in the future.