ZK - Open Source Ajax Java Framework

I've created 2 Zeta forms, one for Builders and one for Customers. Both have a common field companyname. I want the Customers form to have a combobox that has the companynames from Builders and when one is selected have it saved to the companynames field of Customers.

I thought the following would work (a row in a grid):

<row>
Builder:
<combobox id="companyname" model="@{buildersModel.all}"
<comboitem self="@{each=zx9}" label="@{zx9.companyname}" />
</combobox>
</row>

The combobox is filled OK but when I click on Save it comes up with an error message. Some help with how the class has to be written would be appreciated.

Hi CanuckFlyboy,
would you care to share some more details on your implementation and also let us know the error msg and if possible statcktrace?

Thanks
- Ashish