DOCBOOK-APPS: Markup for shell-like typescripts

I'd like to mark something like (unchecked):

<figure>
<title>an simple example</title>
<screen>
<computeroutput>bash#</computeroutput> <userinput>echo input | sed -e 's/in/out/'</userinput>
<computeroutput>output</computeroutput>
<computeroutput>bash#</computeroutput> <userinput>echo input | sed -e 's/in/out/'</userinput>
<computeroutput>output</computeroutput>
<computeroutput>bash#</computeroutput> <userinput>echo input | sed -e 's/in/out/'</userinput>
<computeroutput>output</computeroutput>
<computeroutput>bash#</computeroutput> <userinput>echo input | sed -e 's/in/out/'</userinput>
<computeroutput>output
more output may follow</computeroutput>
</screen>
</figure>

This works fine with %number-screen-lines% set to #f or short
listings.  I do have (define %number-screen-lines% #t) which messes it
up in longer examples (line numbers are missing, text bounces to the
left and back).  From reading TDG, I suspect I abuse these tags
(userinput and computeroutput are inline).  Hm, any hints?

Jochen

-- 
Nicht weil die Dinge schwierig sind, wagen wir sie nicht,
sondern weil wir sie nicht wagen, sind sie schwierig.