Need a headphone/antenna splitter.

I recently bought a Navigon 7100 GPS, which I really like. One small problem though, For some odd reason they combined the headphone and FM antenna (for traffic updates) into one socket. So now I can’t use both at once, which is kind of a bummer when riding my soon to be aquired scooter. The male. which is on the supplied antenna, looks like a regular stereo plug, but has 4 pins and is a little longer. So what I need is an adapter (splitter) with one 1 male and 2 female connectors, both 4 pin, so I can use both devices at once.
The regular 3 pin stereo plug works fine to plug my headphones into the unit, so if both females are 4 pin, that would be fine.
Any ideas when I might find such a thing?
Peace,
mangeorge

A quick Google search turns up this guy who built his own.

Thanks, 3way. I saw that, and can get the cable easily enough. But I assume I’d have to splice the headphone and antenna wires to the cable pigtails.
I was hoping to be able to find something removeble, with females attached to the male cable.
I’m looking for male connectors.
Thanks.