<xsl:when test="contains($Text,$UC13)">

it won't unless the source contains an explicit &#13; reference.
Whatever platform you are on all xml parsers are mandated to normalise
line endings to #10 on the way in.

No need fo a variable, just do 
contains($Text,'&#10;')

David

_____________________________________________________________________
This message has been checked for all known viruses by Star Internet
delivered through the MessageLabs Virus Scanning Service. For further
information visit http://www.star.net.uk/stats.asp or alternatively call
Star Internet for details on the Virus Scanning Service.

 XSL-List info and archive:  http://www.mulberrytech.com/xsl/xsl-list