Recursive Calls To Stored Procedure

I need to develope a stored procedure (eventually called by a trigger) that creates a record in an event table for all the descendants of a drawing. There are 3 tables involved as example tables shown below:



DwgTable


DwgID (integer)--drawing record identifier

PrntDwgID (integer)--parent drawing record identifier (a previously defined DwgID from this table)

DwgEventTable


DwgEventID (integer)--record identifier

DwgID (integer)--value from DwgTable

EventID (integer)--value from EventTable

EventTable


EventID
There are other fields in two of the tables and only the fields shown in the DwgEventTable, but only the fields shown are required for adding a record in the DwgEventTable for a new event in the EventTable. The problem is identifying all the DwgID's of the descendant of the DwgID where the EventID occurred. There may be 0 to N descendants in 0 to N generations. I need to add a record for the original DwgID and all the descendant DwgID's in the DwgEventTable for the event identified by EventID.

I could do this from the client side, but a better place would be from the server side. I need some clue(s) on how to start coding a recursive stored procedure in SQL Server 2005. From what I have read, you cannot create a managed code procedure that appends or updates records--if managed code can add/modify records then I can do the above with managed code procedure.

Any Suggestions?