Can You Multisession DVD-RWs???

I'm trying to do this on a DVD/CD-Burner, a SONY DW-U10A with bundled NTI DVD-Maker 6 Gold, with bad results. (If it matters, I'm using WinXP Pro on a 1,400MHz P-4 with 512MB Rambus.)

The NTI User's manual has a whole chapter on multisession CD-ROMs, but not a whisper of this on DVD-RWs.

Am I trying something imossible?

Thx in advance, folks.