Append HTML to blip does not work

I'm trying to create some wave in the server-side but from HTML markup or to add some HTML markup to a blip.

My code:
final OperationQueue opQueue = new OperationQueue();
final Wavelet newWavelet = opQueue.createWavelet(domain, participants);
final Blip rootBlip = newWavelet.getRootBlip();

if I add HTML markup as described in:
http://www.waveprotocol.org/wave-apis/frequently-asked-questions
it doesn't work:
rootBlip.append(new com.google.wave.api.Markup("<b>foo</b>"));
and let the rootBlip empty. But this (without markup) works:
rootBlip.append("foo");

I suppose (please correct me) that this is some new issue related with the WIAB release as open source, because I remember that this was working with some of my robots in Google Wave. I suppose/imagine that the markup is checked in Google Wave using some internal sanitize code of Google (no released) and now this is broken in WIAB.

If this is a real issue, maybe I can help to fix it if I finally understand more the internals of this part of WIAB.

Looking the suggestion of the header of Markup.java I started to look and play with the client PasteExtractor and RichTextTokenizer* etc to figure out the better way to unrender a html into a blip.

To summarize, now I can create a IndexedDocument or DocInitialization like:
<line><?a "style/fontWeight"="bold"?>foo<?a "style/fontWeight"?></line>
in the server side but after several tests I don't know how to convert this in a new Wave or to modify the rootBlip. Probably I'm following a wrong path to make this.

Any suggestion/tip/orientation welcome.