Hello,
DPM requires a series of requirements in
its implementation.
DPM operates on a table, which
tells us that space needs according to
data source.
I leave you some links that can help.
http://social.technet.microsoft.com/Forums/es-AR/systemcenteres/thread/c38ba295-4458-41eb-8ff1-a47f23da21ac
http://social.technet.microsoft.com/Forums/es-AR/systemcenteres/thread/94ab6b84-f032-489a-99ae-ad12c1cec0be
sorry for my English is very poor.
Also this would be the Spanish forum, but
it can help you understand and count on me.
Greetings.