Please help DVD Multi session burning

[Rick Colborne]

Details are : App Roxio Toast 6.1 / Sys 10.3.3 / G5

I am struggling to burn a multisession on DVD with Toast.
In Toast I just  can't find the right settings, the 'close disc' tab is 
always
grayed out and I have tried various different types of 'burn' eg iso 
900..
Mac & PC etc.
After each session the next session will say "Insert recordable disc'..

Any help would be appreciated. PS - Did check archives, but found zip.
Found nothing on Roxio site either.

Thanks.