determine if a value exist in the following-sibling

Hi,

please anyone can help me with this expression,

i got the following xml :
<amounts>
	<period_id>1</period_id>
	<value>1</value>
</amounts>
<amounts>
	<period_id>2</period_id>
	<value></value>
</amounts>

in my code i have <xsl:for-each select="amounts">  

and i want to test if the next elements of amounts have a "value" or not,
i'm using xslt 1.0 with xalan/apache fop.

NB: i tried with the following:boolean(following-sibling::amount/text())
but the expression is wrong ....

and thanks a lot for you help