Hi,
there are two direct connectivity available for Dashboards:
option 1: using the connection directly from BW which requires BI Java as well, does not require the BOE server.
for that take a look here:
http://wiki.sdn.sap.com/wiki/display/BOBJ/Integration+of+an+Xcelsius+dashboard+in+BOE+Infoview
Option 2: You use BI4 and the Query Browser which can leverage the OLAP connections and then you save normally the dashboards to the BOE server
regards
Ingo Hilgefort, SAP