API - GetProducts only shows custom fields in returned JSON IF "it shows on order form"

[JamesP]

Hi

I am writing an Import script for 4000 customers using whmcs api.

I have two custom fields for my products, which are not visable on the order form, but are vital  for the successful operation of the product ( its a custom module)

 

However, the WHMCS API  getproducts only shows customfields that are ticked "show on order form"  , Unfortuantly that is not an option for these fields as the module calculates their values, and the customer should not be able to specify them.

 

I need the custom field ID values, to then use correctly in an AddOrder API call,  

 

Can anyone think of another way I can get the right ID Values?