Any problems: headsets to handheld?

Folks - I'm having difficulty getting audio from my Avcomm headset to
my Icom A-21 handheld.
The Icom requires a condenser microphone and the Avcomm has an
'electret' element, which as I understand is a variety of condenser
mic.
Has anyone had a similar problem and how was it solved? - Mike

PS- I see a variety of circuitry on the 'net describing how to power
the microphone, but I was hoping not to have to go off building
another box.