(i've already post this in the forum but i think it's more appropriated to post it here)

i'm the inksmoto main developper (xmoto level editor which is an inkscape extension
look at that to see the different possibilities:

Xmoto is a gpl game:
http://xmoto.tuxfamily.org/ )

some times ago, Ted told me that:

"What I would recommend for this is add a custom X-moto namespace on the XML file.
Inkscape will honor this, and keep it in the file. So something like this:

<path d="M 1 1 M 2 2 M 3 3 z" xmoto:vertex-settings="rrg" />

Where 'r' and 'g' mean something about the vertexes of the path."

So i add some path information in my own xmoto namespace:
       d="M 314.29911,415.20982 L 314.29911,98.084821 L 128.58036,98.084821 L 128.58036,415.20982 L 314.29911,415.20982 z"
       style="stroke-linejoin:miter;stroke-opacity:1;fill-opacity:1;stroke:lime;stroke-linecap:butt;stroke-width:1px;fill:#66ddaa" />

with the namespace definition:
(the name ns0 is automatically choosen by lxml)

But, when i do a boolean operation on this path, my ns0:xmoto_label disapeared in the new paths created after the boolean operation...
       d="M 575.875 242.375 L 390.125 242.375 L 390.125 423.9375 L 575.875 423.9375 L 575.875 242.375 z "
       id="path3184" />
       d="M 390.125 106.8125 L 390.125 242.375 L 575.875 242.375 L 575.875 106.8125 L 390.125 106.8125 z "
       id="path3179" />

i've tried with both inkscape 0.45.1 and 0.46 svn from yesterday and the behaviour is the same...

is there a way to keep my informations after a boolean operation ??
(i've also tried putting my informations into inkscape:label, but it's dropped too after a boolean operation)

(and i also confirm the notebook bug, i've having it too with 0.46svn
https://bugs.launchpad.net/inkscape/+bug/169017 )