Case incensitive key

Hello,

Is case insensitive keys possible in XSLT 1.0?  It isn't the end of the
world, as I can simply abandon the key but would rather not.

For sake of discussion, here's my use of a key:

<xsl:key name="key_goty-email" match="row" use="Description/email"/>

<xsl:if test="count(key('key_goty-email',current()/email)) &gt; 1">
....
</xsl:if>

So the current node, Description/email could have something like:
Myemail@xxxxxxxxx
Other potentional key matching nodes could be: myemail@xxxxxxxxx or
MYEMAIL@xxxxxxxxx

Thanks,

Karl..