GetServerAggregateStatsRequest Soap Admin Method

Hello everybody,

I'm trying to use this 'GetServerAggregateStatsRequest' Soap method to retrieve statistics from the server and integrate them with our already existent statistics page. But whenever i call it, the answer is always 'service.UNKNOWN_DOCUMENT'. As i understand, this means that Zimbra does not recognize this request (this method doesn't exist), but it is listed in the soap-admin.txt doc. Is this document up-to-date? If this method indeed exist, how is the right way of calling it? What should the parameters 'statName' and 'period' be? And if this method doesn't exist, as i believe, what would be then the right form of retrieving server statistics?

Hope someone can help me, i'm stuck in this problem since a couple of days already.

Thanks in advance,
Rodrigo