update Item

I'm a new JDE user and I'm trying to use the InsertItemMasterRow business function (DLL = COPBASE, Object Name = B4100290). I can easily create a new item when I fill the right fields (short item number, second item number, third item number and action code). Nevertheless, when I'm trying to update an item, the business function call worksbut it doesn't change the item. Actually I fill the following fields : short item number and action code (= 2 to update) ... I have read in the JDE documentation that if the following fields of the data structure (
szSalesCatalogSection, szSubSection, szSalesCategoryCode3, szSalesCategoryCode4, szSalesCategoryCode5, szCommodityClass, szCommoditySubClass, szVendorRebateCode, szMasterPlanningFamily, szPurchasingrCategoryCode5, mnBuyerNumber,mnLeadtimeLevel,mnPlannerNumber,cOrderPolicyCode
cIssueTypeCode) are blank, then the current value in the F4101 record should not change !! So I suppose that I have to fill these fieds to update my item ... but I don't have any idea what are the values of these fields ! So first can you give me description of these fieds to understand what they do, and where I can retrieve their values using the JDE Web Server !
Thanks a lot for your help.

mcenatie,

These fields should be on the item master F4101. They can be found in the item master search form (P4101) by selecting an item and choosing row exits. Some of them will be on the Item Revision exit, some will be on Category Codes and others will be on Additional System Info row exit.