[XML-SIG] Possible bug in 4XSLT wrt using EXSLT func:function?

[Craeg K. Strong]

Hello:

I wrote the following simple extension function:

<xsl:stylesheet
xmlns:xsl                 ="http://www.w3.org/1999/XSL/Transform"
xmlns:arielpartners = "http://www.arielpartners.com/XSLT/Extensions"
xmlns:func               = "http://exslt.org/functions"
extension-element-prefixes  ="func"
exclude-result-prefixes         = "arielpartners"
version                                     = "1.0">

....

<func:function name="arielpartners:toUpperCase">
    <xsl:param name="stringToConvert"/>
    <func:result select="translate($stringToConvert,
                                      'abcdefghijklmnopqrstuvwxyz',
                                       'ABCDEFGHIJKLMNOPQRSTUVWXYZ')"/>
 </func:function>

....

<xsl:template name="mytest">
     <xsl:value-of select="arielpartners:toUpperCase(.)"/>
</xsl:template>

The above works great in Saxon.   However in 4XSLT, it dies with a 
message of
something like "cannot add integer to string."

Here is the offending line:  (line 350, Exslt.py)

arg_name_list = map(lambda x: 'a'+x, range(len(self._params[:26])))

I don't quite get the reason for this line, but there is definately a 
problem with it...

I would like to check if this is already reported, but don't know how/where
to access the buglist.

Please advise if there is a patch, workaround, etc. or if anyone else 
has noticed this...
Thanks very much!

--Craeg