Well that does not seem to work since the skin cannot be equipped in the loadout section in the campaign. This is weird since the skin is equipable in single mission.
I have downloaded the SF2_ODS_Parts ad I have installed them all correctly, the campaign works with the normal skins. However, when I try to fly a custom skin I downloaded and installed (SF2_F-4E_Mobius) it doesn't load in the campaign. However, it loads fine in the single mission on the same map. I am not sure if it is a problem with the skin or the campaign.