The finance helpdesk published a leaflet on the budget calculation in "FP7 Research for SMEs" projects.

The “Research for SMEs” funding scheme supports small groups of innovative SMEs in solving technological problems and acquiring technological know-how. SMEs subcontract research to RTD performers in order to acquire the necessary technological knowledge. The EU grant is capped at 110% of the price to be invoiced to RTD performers for subcontract work as agreed prior to contract signature.

You can download the leaflet from the finance helpdesk site.