Try placing your text commands and spinning object routine within a loop. You can leave the backdrop on. It works! I done this many times myself both in DBC and DBPro.
Example:
Rem Project: Text Over 3D Example
Rem Created: 5/15/2005 3:32:50 PM
Rem ***** Main Source File *****
sync on:sync rate 60
make object box 1,2.0,2.0,2.0
position object 1,0.0,0.0,0.0
position camera 0.0,1.0,-6.0
color backdrop 0
set text size 50
ink rgb(255,255,0),0
do
center text screen width()/2,screen height()/2,"Text Over 3D"
xrotate object 1,wrapvalue(object angle x(1)+5.0)
yrotate object 1,wrapvalue(object angle y(1)+5.0)
zrotate object 1,wrapvalue(object angle z(1)+5.0)
sync
loop