This is done with Awesome mod installed. Change your sims to career outfit. Then target him/her, and type in the command editsim. This will bring sims back to CAS and you have the option to edit her career outfit set.
I have tested it, my sims did go to work with new outfit as I purposely made it obvious for verification purpose. There are 2 things I have not tested:
- What if sims get a promotion or change job. Would it just replace this custom career outfit and not bug anything out?
- What if the custom items become unavailable (say you remove it from Mods), will it behave like other outfits and find a random EA default item to replace?
Although I would say both answers would be Yes, I have not tested. There is one thing I do know: while re-entering CAS, you will get to see this hidden tab, but when you click away to another outfit tab, this tab with disappear. You should figure this out by yourself easily, and just editsim again if you need to.
For those who might ask, I did try editsim while they go to shower: out of 5 times, CAS gives me Everyday outfit tab. So this is not the way to go into Nude outfit, but possible with Career outfit.
I work for a living, but I don't necessarily live for a working.