DEBUG agi: >>> EXEC SET "SIP_HEADER(x-ahn-test)=rubyrox"
DEBUG agi: <<< 200 result=0

DEBUG agi: >>> EXEC SET "foobar=${SIP_HEADER(x-ahn-test)}"
DEBUG agi: <<< 200 result=0

DEBUG agi: >>> GET VARIABLE "foobar"
DEBUG agi: <<< 200 result=1 (${SIP_HEADER(x-ahn-test)})

DEBUG ahn: ${SIP_HEADER(x-ahn-test)}