DocumentFragment and XBL bindings

Hello everyone,

I try to speed up some dynamic creation of UI elements in my XUL 
application using DocumentFragments [1].

Unfortunately I cannot access methods which were added to XUL elements 
via XBL bindings when these elements are attached to a fragment.

Example:

let fragment = document.createDocumentFragment();
let menu = document.createElement('menulist');
fragment.appendChild(menu);
menu.appendItem(...) // appendItem cannot be found

Is this a natural limitation of fragments and/or is there a way to work 
around this problem? Did anyone had similiar problems?

Thanks & Regards,

Daniel

[1] https://developer.mozilla.org/en/DOM/document.createDocumentFragment