Invoke Oracle Stored Procedure with Collection parameter

Hello,
We have an Oracle stored procedure which is defined as follows:
FUNCTION createshipment (
sitenumber IN NUMBER,
collection IN si_shipmentinfo_objtab,
arcflag IN NUMBER
)
RETURN VARCHAR2

How do I invoke this within webmethods Developer and pass in the parameter which is a ‘collection’ parameter si_shipmentinfo_objtab
The object si_shipmentinfo_objtab is defined as follows:
TYPE si_shipmentinfo_obj AS OBJECT (
tqueue_oid NUMBER,
donor_ctr VARCHAR2 (50),
shipment_nr VARCHAR2 (50),
carton_nr VARCHAR2 (50),
bleed_nr VARCHAR2 (50),
expected_volume NUMBER,
bleed_date NUMBER,
plasma_type VARCHAR2 (50),
vehicle_nr VARCHAR2 (50),
donor_nr VARCHAR2 (50),
test_type VARCHAR2 (50),
test_result VARCHAR2 (50),
test_value NUMBER,
ship_date NUMBER,
part_nr VARCHAR2 (50))

Any ideas?
Thanks.