Thank you for your question. By ‘new items’, do you mean new messages that arrive in the mailbox, or do you mean items that the user creates?
In order to set a category, you first need to grab an instance of the category object from the category definitions collection in the account:
for each oCategoryDef in GroupWise.Account.CategoryDefinitions if (iCategoryName = ucase(oCategoryDef.Name)) then set aCategory = oCategoryDef exit function end if next
Then, given an instance of a message object, you add the category object as shown here:
As I alluded to above, the devil is in the detail regarding the scenario under which you want to add the category.
I hope this helps.