Error due to less than or equal (

Hello,

I've tried the following query in Flash Builder 4.6 : <esri:Query id="query1FR" where = " pw_fre <= '{qText2FR.text}' " which causes an error while compiling with a warning message telling that the value of atribute "where" associated to an element type "esri:query" must not contain the character '<'

How do I query properly in Flex using operators "<" and "<=" , can anybody show me how to do it the right way ?
Thanks already,
Pierre