I don't have either program but with all programs that show those icons here (7zip, Winrar, Avast etc) the icon is compiled into the EXE.

The used format is 16x16 with 16 colors.
If my theory is correct and those programs miss said icon format for whatever reason, you could try the following:
Get a hold of the icon in question, GetIcoFX
IcoFX - The Free Icon Editor
make sure you add the missing format and save the new multi format-icon
Now open the exe in Reshacker and replace the appropriate Icon Group..save, reload and see if it worked
-DG
I assume Derekimo's version would be the way to go