weird key-nodeset behavior

hi,

i asked several questions on key usage, but i could not get an answer for most
of them. I worked on my code for hours.
and at the moment i can say that i have the following problem:
-i try to do a grouping.
-if i try to group on all elements with the key definition, it works, e.g.:
<xsl:for-each select="//dovizler[generate-id(.) =
generate-id(key('dkey',key)[1])]">
-but if i try to do the grouping on a nodeset, it does not work, e.g.:
<xsl:for-each select="$mydovizler[generate-id(.) =
generate-id(key('dkey',key)[1])]"> where $mydovizler is a nodeset composed of
'dovizler' elements.

i am really stuck.

any ideas?
regards...