Batboard

According to Motorola, the microphone extension cable PMKN4033A can only be used with a palm microphone. However, I need to use a microphone extension cable with one of the desktop base stations (XTL2500) but can't find one. As an experiment I did use the PMKN4033A extension with an RMN5070A desktop mic and it keyed the radio and passed audio. But, before I declare that this set-up can be used I want to make sure I'm not missing an important piece (or pieces) of information that would illustrate why this mic extension cable can't be used with desktop microphones.

Thanks,

Ed