How a field of table type is got separated from a zstructure while creating a odataservice

Hi Experts,

I have created a zstructure in se11, which contains three fields including one field of type "TableType".

field1 type char1,

field2 type char2,

field3 type zchar3_tt.

when ever i created a service using this structure , it automatically get splitted in to two different entity types .

entitysetname   "which is given

field3                " which is of type zchar3_tt

in entity set method, after getting the result i passed it to ET_ENTITYSET.

but to my surprise the field(field3) of type TableType is not present in the set.

Et_entityset(0x2)  = lt_ztr (0x3).

so, my query is how it got seperated from the et_entityset and what to be done to make it appear in et_entityset.

here et_entityset and lt_ztr are both derived from the same structure(zstructure).

Kindly help me in resolving this issue.

Thanks in Advance

Best Regards,

Anand.