I found this link and this should work. http://developmentnow.com/g/115_2005_11_0_0_629283/Scheduling-outside-SRS.htm

You basically create a phony subscription then go to the reporting services database on that server. Get the information you need from the subscriptions table. run dbo.addevent with the correct values and it will run the report.

So i put this logic into a stored procedure that checks if its the last day of the month then it will run the report.

Now just schedule a job to run daily.