First, look at the processing options for P4021 and find the Supply & Demand Inclusion Rule code being used (e.g. S&D).
Next, go into the Supply & Demand Inclusion Rule application (P34004) for this code, and delete any entries for WB orders. Note that when you change this, everyone using this Supply & Demand Inclusion Rule code will be affected -- it's not a personal setting.
I haven't been any more specific because I don't know what version of E1 you're running. This is why it's always a good idea to put your system configuration into your post or your signature.