How to get Asterisk to answer (AA) via SIP phone X-Lite, fla

Hi,

how to get Asterisk to answer (AA) via SIP phone X-Lite, flaphone ?

In stand -alone installation of Asterisk I just need to call Asterisk server and test dialplans, MusicOnHold, voicemail and more.

I am using audio channel for Asterisk, Celliax, to have Asterisk to play audio via sound card.

The problem is sound quality.

At the same time Asterisk can play the same audio files fine via registered X-Lite SIP phone
and sound quality is good.

Is it possible to control Asterisk, select dial plans via DTMF codes sent to SIP phone , X-Lite in
auto connect mode.

To say it in another words.
Given X-Lite registered to Asterisk in auto answer mode , can X-Lite select numbers, context
dialing done via sending DTMF codes remotely to a sound card (mic, line in)
using DTMF dialer ?

Or keyboard keys of X-Lite or another SIP softphone must be selected to generate DTMF codes + ENTER
to get internal number + context selected ?