maybe i am wrong, but isn't it even better, to use BS components instead of "own" components.
for example clamscan. ispconfig uses clamscan in /home/ispconfig/tools/clamscan/... (if i remember correct).
if there is a newer version of clamscan, i have to wait for a ispconfig update and to update my server. i am using some "self-patched" scripts, so i have to update to a never ISPConfig version and then i have to "re-apply" all the patches (and not to forget any of them). this means i do not do any ispconfig update if i don't need to do it.
if ispconfig uses the (in my case) "debian" clamscan i only have to do
to have the newest clamscan installed. i think, this is even easier to do and no one had to wait until there is a new version of ispconfig (and the developer haven't to make a update because there is a never version of clamscan).