select="//Row[NUMERO = (1, 2, 3, 4, 5, 6, 7, 8)]"
is working !!!! (and a lot more faster...)

If speed matters you could of course define a key
  <xsl:key name="k1" match="Row" use="NUMERO"/>
and then use
  select="key('k1', (1, 2, 3, 4, 5, 6, 7, 8))"

	Martin Honnen
	http://msmvps.com/blogs/martin_honnen/