Parsing syslog message to database

I've got a script to parse elements of the syslog message into Fields.VarCustom01 and 02 (tested and working.)  I've also got a rule to log to SQL server and setup a custom DB format for the two custom fields (tested and working.)   How do I get the Fields.VarCustom0X value to go to the MsgCustom0X field in the database?   The action are setup to run the script then log to the database. 

Thanks in advance for any suggestions
Bill