How can I use freemarker variable inside JSP tag?

I would like to use variable calculated in freemarker inside Struts tag. How can I do this in following situation:

<#assign val0=100 />
<#assign val1=1000 />
<@s.select value="开发者_运维问答amount" name="amount" label="Amount" id="amount"
list=r"%{#{val0:'text100', val1:'text1000'}}"/>

Currently this select is empty.

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You access custom variables the same way you access variables from the data model.

${val0}