Need header in message when whitelisted by custom function

[Jan-Piet Mens]

Hello,

when whitelisting a message with

	Is Definitely Not Spam = &JPscan

I'd like a header added to the message. Anything would do, but something
to the tune of

	X-whitelisted: yes

would be ideal, and I'd ideally like to create that header from my
custom function.

Is there a way to do that with version 4.43.8 [willing to upgrade] ?

Thanks & regards,
	-JP