combobox and null value

[alberto01]

Hi,
I have a form with a combobox "parent_reseller_ref". The combo is filled with the loadRecord method of the form.
The record is specified in a store in this way:

{name: 'parent_reseller_ref', 
type: 'int',
useNull: true
}

The record is populated from this json:

{rows: [network: "test nw", parent_reseller_ref: null, zip: "00100"]}

The problem:
If in the json the value is "null" and i don't specify "useNull", the combo will be populated with a 0 (int) value.
If i specify "useNull: true", the combo wille be populate with a null value, but in the json produced submitting the form (method POST and PUT) , i got an empty String! parent_reseller_ref: ""

any ideas? How ca i force to produce a null value against a string?

thank you .
A.

[willigogs]

Could you return more of your code in order to help diagnose the issue?

i.e - the fields, store, combo, etc