ancestor problem

Helo list,
I am kind of newbie with xsl and I have the following (really anoying) 
problem :

I have a xml doc like this:

<result>
	<left>
		<ligne>
			<couleur>987656</couleur>
			<ligne>
				<couleur/>*
			</ligne>
		</ligne>
		<ligne>
			<couleur>666666</couleur>
			<ligne>
				<couleur/>*
			</ligne>
		</ligne>
	</left>
</result>
	
Is there a way to get the value of the first level couleur while 
processing the second level ligne ?

I process something like apply-template match:"//ligne/ligne"

I tried with this xpaht expression : <xsl:value-of 
select="ancestor::left/ligne/couleur"/>

But I get a list of all first level couleur...

Any ideas would be **greatly** appreciated !!

Thanks for your attention,

Schlum