BLF support in Asterisk

Asterisk version 1.4.x breaks support of the BLF function on Grandstream's GXP 2000 phones. We need someone that can fix this matter and makes BLF functioning again. Status LED are always green and even if there is an active conversation or some internal line is not registered LED doesn't change color (should be red color). LEDs are configured in "Asterisk BLF" mode. We are using Asterisk v1.4.6. We made tests with Asterisk v1.2 and this problems doesn't shows up so I believe that is v1.4.x specific.