PayBox HMAC key changing without any action...

[lfdpda]

Hi all,

I can't figure out how it can happen but the facts are these : I configure a valid HMAC key and I can test payement without any problem using any browser (firefox, IE, Chrome...). I can test it ten times and it works. Then, my customer tries it and it works once or twice, then the customer complains about error. PayBox returns that HMAC key is wrong. So I check it into the payment configuration and indeed, the HMAC key has changed. How is it possible ? At this time, if I re type the correct key, it works again ... until the customer makes some tests.
Note that I've changed admin Password so I'm sure that nobody but me can connect to administer the website.
Any idea ? Does anybody knows where this key is stored ? In a file ? In database ? (I'm not a joomla / Virtuemart expert).

Thanks in advance for any suggestion.