The pre/post scripts seem to be depracated, in later NetBackup/VCB integrations as you rightly say.
However, interesting article over at the VMware Infrastructure Operations website. (URL below)
It uses the vmware tools in the guest for the pre and post.
It details some interesting information about VCB, and that Custom VM Quiesce scripts should reside inside the VMware Tools subfolder.
Page 6 of the article
All custom scripts placed in the backupScripts.d directory will be analyzed during both the pre-freeze AND post-
thaw events. This means that logic needs to be placed in the script so that the desired result is gained. If no “IF’
statements are contained in the scripts, they will be executed during both the pre-freeze and post-thaw events,
which could be undesirable.
A script should contain statements similar to the following:
IF “%1%” == “freeze” goto doFreeze
goto postThaw
:postThaw
IF “%1%” == “thaw goto doThaw
goto fail
:doFreeze
net stop mysql
goto EOF
:doThaw
net start mysql
goto EOF
:fail
echo “$ERRORLEVEL% >> vcbError.txt
:EOF
References:
http://viops.vmware.com/home/docs/DOC-1392
http://viops.vmware.com/home/message/1125
http://communities.vmware.com/message/1017118
Good Luck let us know how you get on.