ejb 3.0 should include the so called "business logic"

if i have jsf which also is built on the model-view-controller pattern, with ejb, where i have to put the "business logic"

example...
i have a cart
carts will saved through requests by stateful ejb
to add or remove items in cart -> this can happens in ejb

i have a list to show
should i prepare all complete data from ejb an give back a list to the modell fkt of jsf or should i do it all in modell object

where can one decide

whats your opinion