2 possibilities from what I can see
1 the output level of the gate is not enough to open the envelope
2 the length of the gate is too short to open the envelope
you'll need to check the output level of the gate in the manual... and cross reference it with the doepfer module
adjusting the length of the gate on the west pest is addressed on page 16 of the pdf manual
"some of the best base-level info to remember can be found in Jim's sigfile" @Lugia
Utility modules are the dull polish that makes the shiny modules actually shine!!!
sound sources < sound modifiers < modulation sources < utilities