Monitoring CISCO ASA5520 using SNMP v3

I am trying to set up SNMP v3 to monitor a Cisco ASA5520, I am configuring the NPM side and an engineer is setting up the CISCO side.

We are setting it up for Authentication - MD5

Privacy/Encryption - AES128

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When he puts in a Hexadecimal password for both for example f0:f0 the authentication fails, at the NPM end I have tried putting the password in without the colons but it doesn't make any difference.

It works fine when he uses a plain language password, has anyone got the hex passwords working and if so how, advice please.

Thanks,

John