Codec L16@8000h support

Codec L16@8000h support

im working with FreeSWITCH Version 1.10.10-release+git~20230813T165739Z~4cb05e7f4a~64bit 
im trying to get FS to do transcoding between codec L16@8000 on inbound leg to PCMA on outbound leg, I've tried several configurations without any success, I continue getting:

488 Not Acceptable Here
Reason: Q.850;cause=88;text="INCOMPATIBLE_DESTINATION"

im stuck, any help, welcome 

my configuration:
vars.xml
  <X-PRE-PROCESS cmd="set" data="global_codec_prefs=L16@8000h,PCMA"/>
  <X-PRE-PROCESS cmd="set" data="inbound_codec_prefs=$${global_codec_prefs}"/>
  <X-PRE-PROCESS cmd="set" data="outbound_codec_prefs=$${global_codec_prefs}"/>
  <X-PRE-PROCESS cmd="set" data="rtp_alias_map=10=L16@8000h"/>

external.xml
  <param name="rtp-map" value="10=L16@8000h"/>

dialplan:
 <extension name="test_codec">
   <condition field="destination_number" expression="^(\d{10})$">
     <action application="bridge" data="{}sofia/external/$1@1.2.3.4"/>
   </condition>
 </extension>

Request INVITE SDP:
s=Asterisk
c=IN IP4 1.2.3.5
t=0 0
m=audio 19596 RTP/AVP 10 101
a=rtpmap:10 L16/8000
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-16
a=ptime:20
a=maxptime:60
a=sendrecv