How can you buy an HD movie if you already have an SD Digital Copy?

Hi All...

So, over the years I have purchased Blu-Rays and DVDs wthat have come with digitial copies. With the advent of iCloud, some of these movies show up as "purchased" on my TV and in iTunes. Some don't...which I assume has to do with rights issues...but that's another story ;-)

So, here's my question...

When I go to, say, "Batman Begins," it shows up on TV with a "Play" option because it knows I have it in my iCloud library. But...what's there is the SD version. What if I want to purchase the HD version now that it could be in the cloud and thus, over time, start to eliminate my optical disks?

I thought about, perhaps, just buying the HD version from the iTunes store itself, but don't really want to spend the money without knowing how TV is going to deal with having two purchased versions of the movie available to it.

Has anyone experienced this before?

Any direct experiences that could help me would be most welcome...

tks,

rwr