DVD/UDF question

I burned a DVD Data disk a couple days ago, and upon sticking it back in the drive and checking it’s properties via Windows Explorer, I noticed it said something along the lines of 1.99gb instead of it’s correct size of nearly 4gb.

I know I’ve seen DVDs say their correct size before, so I stuck another DVD Data disk in the drive (a retail game - Tex Murphy: Overseer), I noticed the file system was UDF instead of CDFS like the data disk I burned had said.

I checked a few other DVDs (retail games and movies), and they all had UDF. So I figured this must be what’s allowing the DVD to show the correct size. I did a bit of research and also learned that UDF disks can also have longer file names than Joliet and show the correct file names when inserted into other systems such as Macs.

So I burned a DVD Data disk with ISO 9660 Level 1 and UDF 1.02. I put it in my DVD-Burner and it’s read perfectly fine. But when I put it in my Creative Encore 8x, it never shows up; I try to select it and I get that error saying a device must not be connected.

Is this a normal occurance? Why would my Encore read UDF disks perfectly fine if they’re retail, but not if I burn them? If it can read all other UDF disks, shouldn’t it be able to read these? o_O?

Oh, and yup, I did finalize/close the disc during burning.