TLDR; How to you change the domain that is displayed in inbound sip uri caller-id?

When somebody calls me at sip:tom@mydomain.com:5080, the call is transferred to my extension, where it rings through on my Nexus 4, which is registered to that extension.

If somebody at 1004@remote.org calls me, my caller id is showing 1004@mydomain.com, which is incorrect.  They are not registered on my system, so I would prefer to see 1004@remote.org on my caller id.

What variable would I use to set the domain portion of the caller id?  Modifying name or number, as shown below, simply results in test_number@mydomain.com

How do I get it to quit displaying mydomain.com and start displaying the domain of the incoming caller?

  <extension name="toms public sip uri">

    <condition field="destination_number" expression="^tom$">

      <action application="set" data="effective_caller_id_name=test_name"/>

      <action application="set" data="effective_caller_id_number=test_number"/>

      <action application="transfer" data="1000 XML default"/>

    </condition>

  </extension>