Using Media Center Studio you can edit the Media Center Start Menu strips and icons. If you want to move the new Netflix and Internet TV icons to a custom menu strip you can!
Create a new custom menu or use an existing custom menu such as the one My Movies creates.
In this case I just created a new custom menu called custom menu.
Then move Promo (Movies1) for Netflix and Promo (Browse TV) for Internet TV to your custom menu strip. Save the changes in Media Center Studio.
Open Media Center and the Netflix and Internet TV icons should now appear on your custom menu strip.
Thanks to Advent for the tip about using the promo tiles.