You can set any outfit as outerwear by using SimPE (add 1000 to the "category" line in Property Set, so if it says something like 0x0000257, write 0x0001257 instead - look here if you need tips), or by using the Wardrobe Wrangler. 

If you don't want to use any of them, you can make a clone of the outfit in Bodyshop, and set the categories there. You'll have double clones of all the outfits, so make sure you delete the old set.

If the clothes are tops/bottoms, you have to use SimPE to set hem as outerwear (and yes, you can have tops/bottoms as other categories than everyday). You can also change catgories for horns and such, if they're not showing up in Outerwear.

The WW is a lot easier to wrap your head around than SimPE if you're new to this, so if you don't want to learn a lot of new things, go for the WW. It's quite intuitive for working with clothes.