You can copy it to a new column, then:
1. Click the column header, in the pop-up mini toolbar, choose Categorical.
2. Click on the edge of the worksheet, choose Show Category Indices in the worksheet mini toolbar.
The script can be:
colcopy irng:=1 orng:=2;
wks.col2.ISCAT=1;
wks.CATI=1;
James