Odata, Reading Custom Header Problem

Hi Experts,

how can i read custom http header inside my DPC_EXT class. i am using gateway client there i am creating one custom HTTP header like below

Name : Mytest

value :mytests value

i am sending request using GET method

inside my DPC_EXT method i am using below lines to access http header , but i am not getting.

Data : Lo_facade type ref to /IWBEP/IF_MGW_DP_INT_FACADE,

lt_client_headers type TIHTTPNVP.

lo_facade ?= /iwbep/if_mgw_conv_srv_runtime~get_dp_facade( ).

lt_client_headers = lo_facade->get_request_header( ).

Regards

Saumya