SYCUSTNV has got all functions related to Customer information. In order to add fields from ARMAST, you need to refer to SYECRMNV.PRG.
Following are the steps:
1. Modify syecrmnv.prg.
2. Find the Method “m_GetARInquiry” and add your custom field name where all the fields are added. (Please note that your custom field should be there on both the tables i.e. ARMAST and ARYMST)
3. After adding the field, save and compile the syecrmnv.prg file.
4. Here you need to re-build SYCUSTNV.DLL.
5. After this, you need to register the DLL onto Sage CRM Server.
6. Now you need to make the changes into the ASP pages to display the field onto the Sage CRM AR Inquiry Grid.
Please note that in order to accomplish above, one need to have thorough knowledge of PRO Customization and build process of sycustnv.dll.