I have created a MultiProvider containing two DSOs, both without any key figures (in queries I have the key figure 1ROWCOUNT). I cannot select 1ROWCOUNT as a Key Figure in the MultiProvider and hence I am unable to activate the MultiProvider since it doesn't contain a Key Figure.
In 3.0B you could include 1ROWCOUNT in MultiProviders. From SAP Note 534058:
As of Support Package 10 for BW3.0A (SP03 for BW3.0B), each InfoProvider of the InfoObject or ODS type has the key figure 'number records' (1ROWCOUNT). (This key figure has always been availabe for InfoProviders of the InfoSet type).
In addition, this key figure is also supplied in every MultiProvider containing a part provider of the InfoObject type ODS or InfoSet.
Has this option been removed for BI7.0 or am I doing something wrong?