extended function keys all trigger screenshot

[Bert]

I have made a arduino keyboard with F13 to F24 like you sometimes have on a enterprise keyboard aka battleships for hotkeys.
Steam does make screenshots on all of those keys. Any suggestions how to get rid of that problem?
I do not need screenshots at all, maybe some way to disable it without loosing the overlay entirely?
Thx in advance!

[ReBoot]

Disable the screenshot functionality or set a different key. F11 or anything else.

[Bert]

I thought i described that in enough detail.
Steam does not care what button is set, i have 12 default screenshot buttons at all times.
The only solution without a config file is no steam overlay.

I can't wait for more 'solutions' which apperantely can not work at all.
You can not disable screenshot functionality in steam, you can only unbind the key.