ant ftp action=chmod 755 directories ONLY

Hi, I already have an Ant build file which works fine but I also need to set file permissions via ftp but I'm struggling to work out the syntax.

I need to change just directories, from the base directory down, to 755. I already have code for changing just files to 644.

code:
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<ftp action="chmod" chmod="644" remotedir="/apache-tomcat-5.5.15/webapps/${app.name}/WEB-INF/" server="ftp.csd.abdn.ac.uk" userid="userid" password="password"> <fileset includes="**/**"></fileset></ftp>

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Thanks.