Try the "dfm quota mailformat" command. The help doesn't give much, but I pulled out this information:
FROM: is the keyword that precedes email address to be used in the from field. The keyword is case sensitive and has to be at the beginning of the line.
from-address is the email address that appears in the 'from' field of the quota alert sent to user.
SUBJECT: is the keyword that precedes subject of the message. The keyword is case sensitive and has to be at the beginning of the line.
subject is the subject of the email message.
BODY: is the keyword that appears by itself at very beginning of the line. The keyword is case sensitive. This keyword must appear after FROM: and SUBJECT: keywords. All the lines following the line that contains BODY: are treated as part of the body of email.
Any words in subject or body that begin with DFM_ are treated as dfm variables and replaced by their values. The following are the valid variables.
DFM_EVENT_NAME is the gui style name of the event
DFM_QUOTA_PATH is the name of path that caused quota event
DFM_QUOTA_USED_PERCENT percentage of quota used
DFM_QUOTA_USED quota space used in bytes (or GB, MB, KB) for this path
DFM_QUOTA_TOTAL total quota space available in bytes (or GB,...) for this path
Lines preceded with a '#' character is treated as comments.
Blank lines are ignored.
Comments and blank lines can not appear after line containing BODY: keyword. If they do, they are treated as part of the email body.