panasonic kx-ut13x BLF in asterisk

1) Download sources of asterisk version 1.8.9.3 http://downloads.asterisk.org/pub/telephony/asterisk/releases/asterisk-1.8.9.3.tar.gz
2) Apply patches to add support RFC 4662 from https://issues.asterisk.org/jira/browse/ASTERISK-19516
3) Compile and install
4) Add to sip.conf :

[general]
subscribecontext = presence
……..
[rlist]
type = resourcelist
context = presence
monitor = 10
monitor = 11
monitor = 12
monitor = 13
monitor = 14
monitor = 15
………
5) Add to extensions.conf:
…………..
[presence]
exten = _XX,hint,SIP/${EXTEN}
……………
[internalcontext]
exten = _**XX,1,Pickup(${EXTEN:2}) ; this is for direct pickup
exten = _XX,1,Dial(SIP/${EXTEN},,${DIALOPTIONS})
…………….

6) Configure phone from web interface :

Telephone > Call Control > Direct Call Pickup: **
Telephone > Call Control > Line x > Resource List URI: sip:rlist@{ip_address_of asterisk}
In section Telephone > Flexible Button Settings select type BLF and extension as Parameter for eaсh button