Dear ALL,

Thats my first post here. I am struggling for some time with DTMF issue.
Let me introduce you my configuration.

The main task is to configure RTP Proxy with full topology hiding - OPERATOR_1 ------- Freeswitch ------- OPERATOR_2
Here is a prt of my config:
- sip profile.
I have one new sip profile with two gateways (OPERATOR_1 and OPERATOR_2)
<include>
  <gateway name="OP1">
    <param name="username" value="X1.Y1.V1.Z1"/>
    <param name="password" value="09321234"/>
    <param name="proxy" value="X1.Y1.V1.Z1"/>
    <param name="from-domain" value="test.com"/>
    <param name="register" value="false"/>
    <param name="caller-id-in-from" value="true"/>
    <param name="extension" value="test"/>
    <param name="extension-in-contact" value="true"/>
    <param name="outbound-codec-prefs" value="$${outbound_codec_
prefs}"/>
    <param name="disable-transcoding" value="true"/>
    <param name="inbound-late-negotiation" value="true"/>
  </gateway>
</include>

- dialplan
<include>
  <context name="public">
        <extension name="term">
                <condition field="network_addr" expression="^(X1\.Y1\.V1\.Z1|X2\.Y2\.V1\.Z1)$" break="on-false"/>
                <condition field="destination_number" expression="^46(\d{9})$">
                <action application="set" data="proxy_media=true"/>
                <action application="set" data="bypass_media=false"/>
                <action application="start_dtmf"/>
                <action application="bridge" data="sofia/gateway/OP1/$0"/>
                </condition>
        </extension>
  </context>
</include>

Everything is fine, but i have problem with DTMF conversion from RFC2833 to inband.
Refering to http://wiki.freeswitch.org/wiki/Misc._Dialplan_Tools_start_dtmf and http://wiki.freeswitch.org/wiki/Proxy_Media i have done all the necessary things.

vars.xml
  <X-PRE-PROCESS cmd="set" data="global_codec_prefs=PCMA,G.729,PCMU,GSM"/>
  <X-PRE-PROCESS cmd="set" data="outbound_codec_prefs=PCMA,G.729,PCMU,GSM"/>

The after-effect is following output:
[ERR] switch_core_io.c:1055 Codec PROXY PASS-THROUGH encoder error!

Placing  <param name="dtmf-type" value="none"/> does not help anyway.

Could sb point me where the problem is located?

Thanks in advance,
Mac