last_logon SQL mapping

[viper]

Hi

I have been attempting to do a mapping on the last_logon plugin. I have 
been reading the documentation on mapping. is there any way to customise 
a little more and create a individual SQL query for each of the 
functions SELECT and UPDATE, my current SQL setup has the username and 
domain in separate tables and my user_query and password_query are 
concat which I do not believe can be defined in the dictionary map 
process, I was also wanting to use datatime as the saved field but it 
seems only the unix timestamp is used. If there is any way to create a 
fully custom query that can be executed I believe this would allow me to 
preform the action am looking for in the same manner as the user_query 
and password_query

If anyone has any suggestions please let me know

Regards

Craig