xslt 1.1

There is needed, along with a function to translate uppercase to lowercase,
the ability for position() to take a node as an argument, and return the
-relative- position.
For example: 
<xsl:value-of select="position(following-sibling::truck[1])" />

would return: "3"
for the following node-set:

<tank /> <- context node ->
<car />
<cycle />
<truck />

Currently there is no way in the xslt spec of comparing relative positions
of different kinds of elements.
Cheers,
Matt