Hi Danny,
It looks to me that you are using the syntax from FP4 version of the studio.
As with 1302/1305 this is the syntax
Multiplicity
The syntax of multiplicities has changed for the
definition of both business objects and business object extensions. You now
express multiplicities as follows: [0,1], [0,n], [1,1], and [1,n].
Hope this helps
John Meadows
+ 44 7449 944666