Play a file to callee before transfer the caller

I have a little problem since a few days and i found no answer. Maybe someone can help me what i make wrong here.

I have a incoming number that will redirect to an special extension 301 that redirect the caller to an outside number (the callee).
Now i have played with the option to play an sound file to the callee before the call will be complete transferred. A(x) - Play an announcement to the called party, using ‘x’ as the file.
The announcement should only play the the callee and not to the caller.

here is my extension
; EXTERNAL-PHONE-201260147953b1209d5f922
exten => 301,1,NoOp(local calling internal phone: 0401111111 - <301>)
exten => 301,n,Set(CDR(InternalCalleridNum)=301)
exten => 301,n,Set(CALLED=301)
exten => 301,n,Dial(SIP/SIP-PROVIDER-66860469553ba70d059e36/0402222222,tA(/storage/usbdisk1/media/sounds/announcement.gsm))
exten => 301,n,Hangup()

i have played with the also with
exten => 301,n,Dial(SIP/SIP-PROVIDER-66860469553ba70d059e36/0402222222,tA(announcement.gsm))
exten => 301,n,Dial(SIP/SIP-PROVIDER-66860469553ba70d059e36/0402222222,A(announcement.gsm))

The phone of the callee ringing and after or before pickup the caller its not playing the file.
What i make wrong here?
Maybe i make the wrong way and i should use an additional manual dial plan for announcement on outgoing calls on this extension?

regards and thanks for help

Sound files normally do not include the extension. That allows asterisk to choose the best extension from multiple files.