[NTG-context] cropping text

Hi all, I've used \doboundtext so far, to crop my text exactly as I want it. But now I've problems with text, that contains a \underbar token. It seems, that \handletokens can't handle \underbar. The other cropping alternative, \limitatetext, perfectly works with \underbar, but it's useless for me, as it cropps off only at word boundaries. mhh.. Is there an (more or less) easy way to solve my problem? I don't need a full solution; any hints are welcome. Thanks in advice, Peter