When you save it using the GUI, the landesk agent install gets written to the sysprep file. All you would need to do is find your OSD script, right click on the script and choose advance edit. 2 windows should pop up. One is the actual OSD script, the other is the sysprep file. Just delete the lines that is installing the agent.
On an XP sysprep file it would look like this:
[GuiRunOnce] Command0="c:\ldsleep.exe 30" Command1="net use \\coreserver\ldlogon password /u:domain\user" Command2="cmd /q /c \\coreserver\ldlogon\wscfg32.exe /F /L /STATUS /NOREBOOT" Command3="cmd /q /c del /q c:\ldsleep.exe" Command4="cmd /q /c del /q c:\ldiscan.cfg"
Manually edit and then save the inf, something like this:
[GuiRunOnce] Command0="cmd /q /c del /q c:\ldiscan.cfg"
Thats great - many thanks for that.