In the DSLaunch tree view, click on DS500.ini. It should be near the bottom of the Utilities section.
Find the following section:
[devasync.dll]
;Dump=1
COM1Enable=1
COM2Enable=1
COM3Enable=0
COM4Enable=0
ModemEnable=1
COM8Enable=0
COM7Enable=0
COM6Enable=0
COM5Enable=0
COM2=4,3,2,0,0
COM1=4,3,3,0,0
Change the highlighted line to COM8Enable=1
.
Close DSLaunch and run it again. The link editor will now offer COM8 as one of the selections.