How to use extract the element value using xpath

Hello,

I am having following elements in the XML.
<AdditionalObjectAttributeList>
							<AdditionalAttribute>
								<AddAttribDefID>1</AddAttribDefID>
								<AttribValue>300pt</AttribValue>
							</AdditionalAttribute>
							<AdditionalAttribute>
								<AddAttribDefID>2</AddAttribDefID>
								<AttribValue>400pt</AttribValue>
							</AdditionalAttribute>
						</AdditionalObjectAttributeList>

Through my XSL. I want to check the <AddAttribDefID>
element. If it is "1" then I need to access
<AttribValue> store it as "Width"

if it is "2" then I need to access the following
<AttribValue> store it as "height"

I tried the following expression.. it is not working..
Any help..

	<xsl:variable name="Tiffwidth"
select="./AdditionalObjectAttributeList/AdditionalAttribute/AttribValue[preceding::text()='1']"/>
						<xsl:variable name="Tiffheight"
select="./AdditionalObjectAttributeList/AdditionalAttribute/AttribValue[preceding::text()='2']"/>


thanks
regards,
Arul


		
__________________________________ 
Do you Yahoo!? 
The all-new My Yahoo! - Get yours free! 
http://my.yahoo.com