why disable_hold is not working? i set <action application="set" data="disable_hold=true"/> in the dialplan and also 

<param name="disable_hold" value="true"/> in sip profiles, nothing happened.

another question is, disable_hold is described as a channel variable, i wonder how FS affects the channel by setting 

<action application="set" data="disable_hold=true"/> in the dialplan? for example,

    <extension name="disable_hold">

      <condition field="destination_number" expression="^(11[01][0-9])$">

<action application="answer"/>

<action application="set" data="disable_hold=true"/>

      </condition>

    </extension>

in this extension, which one, the calling party or called party, will be disabled?