That code should work, if `sabcmd ...` is returning a value.
Try testing it by breaking that secion of code into two chunks: 
my $sabcmd = `sabcmd $boilervalues{'XSLTPath'}\\$xsl $xml`;
print "SABCMD: $sabcmd\n";
$_ =~ s/<!--PERLINSERT:transformXML-->/$sabcmd/gi;

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In reply to Re: Executing an app and returning output in a regex. by kilinrax
in thread Executing an app and returning output in a regex. by Gibble

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