Try using Feature LGMST to default WT on IT0008.
If you are using Indirect Valuation (see V_T511), the Amount should be defaulted automatically.
If not, then look at Sankarsan's suggestion,
or use table T510 to indicate that for Country Grouping xx, Pay Scale Type xx, PSA xx and ESG Grouping x, WT xxxx will have a value of x.