What version of BES are you using, and what platform?
For Exchange, there is a field in the userconfig table called ActivationTime you can use. Here a query I use that may help you out:
Code:
select
a.DisplayName,
convert(varchar(10),a.CreationTime, 101)CreationDate,
convert(varchar(10),a.ActivationTime, 101)ActivationDate,
b.MsgsForwarded,
b.MsgsSent,
convert(varchar(10),b.LastFwdTime, 101)LastFwdDate,
convert(varchar(10),b.LastSentTime, 101)LastSentDate
from userconfig a, userstats b
where a.id = b.userconfigid
order by a.displayname