[Q] Key mapping for bluetooth headsets.

I have the Samsung HS3000 headset and I´ve noticed that it behaves differently with different roms. On HTC Sense rom, when in camera app, pressing the call button takes a picture but not with other roms. So I was wondering, is custom key mapping possible on that level? Could I assign the "call" button to launch Google now or do other neat things?

I found a file undersystem/ust/keylayout called AVRCP.kl, is this the file? Can I edit the commands to launch programs?

# Copyright (C) 2010 The Android Open Source Project
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
#
#
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

# Key layout used for Bluetooth AVRCP support.

key 200 MEDIA_PLAY WAKE
key 201 MEDIA_PAUSE WAKE
key 166 MEDIA_STOP WAKE
key 163 MEDIA_NEXT WAKE
key 165 MEDIA_PREVIOUS WAKE
key 168 MEDIA_REWIND WAKE
key 208 MEDIA_FAST_FORWARD WAKE