[Exist-open] exclude whitespaces in search results/ lucene character manipulation

[Caesar, I. <ca...@rg...>]

Dear all,

my TEI-Code is e.g.

pre<lb/>g<choice><abbr>ũ</abbr><expan>un</expan></choice>tò

A fragment from my collection.xconf:

<text qname="tei:div">
                <ignore qname="tei:abbr"/>
                <inline qname="tei:choice"/>
                <inline qname="tei:expan"/>
                <inline qname="tei:reg"/>
                <inline qname="tei:lb"/>
            </text>

Beside that I'm using a callback function (attached) to exclude that <abbr> is displayed in the search results. What I get when I search for preguntò is:
pre g un tò

My questions: 
How can I force the machine to display preguntò whitout whitespacing?
(New topic!) Can I tell lucene e.g. to find all " ō " characters when I search for a simple " o "?

Many thanks ahead. 

Regards
Ingo