Nice one Jagger :)
It seems the principle here is just to fool Poser into thinking the comment is a relevant bit of code.

After reading your last post, I tried your method on a CR2 (not a PP2), and it worked, but the comment got truncated at, I think it was 32 characters. I though the "name" string in a "valueParm" might be a good place to store a comment in a comment in a CR2, as I knew that an unused valueParm does not get stripped out in a resave. I put the following text in the "channels" section of the "BODY" element of Posette:

valueParm COMMENT
{
name Comments_a123456789b123456789c123456789d123456789e123456789f12345
}

There are 65 characters in this "name" string (I don't know the limit), the string was preserved through a resave, as expected. Poser created an entire ValuParm channel, and changed the internal name of the channel to "valueParm 3456789d123456789e123456789f12345", note that it used the last part of the string for the name, not the first.

I then tried inserting a "valueParm" channel in the Poser "box.pp2", with the folloing code:

valueParm QT1Comment
{
name This is a comment!
}

Upon resave the "name" string was preserved. Again the entire channel was built from the fragment I inserted, and this time internal channel name was NOT overwritten.

I don't know why the internal channel name kept getting overwritten with text from the "name" string, in the CR2, but this does seem like another way of inserting fairly long comments like copyright notices, in PP2's and CR2's. The whole string can be read and edited from the interface by double clicking on the parameter dial, and of course the dial can be hidden by setting "hidden 1".

Undoubtedly there are lots of other places in Poser files where this sort of comment can be inserted, any name string would have to be a good bet.

As for inserting coding comments at the relevant place in the code, it looks like we are still stuck with "//", and loosing it if the character or prop is resaved from within the Poser interface.