Not sure if anyone else has tried integrating UMA with UCC and UIS, but I didn't see integration yet for equipping clothing on UMAs using UIS.
I created the attached script (which is very basic) but it seems to do the job. You create clothing items like you would other items, but leave the pre-fab as None when creating it using the UCC Item-->New Item. Just update the prefab by adding this script to the newly created prefab and set the UMA wardrobe recipe and slot name. If you need to hide meshes, you just do it on the UMA recipe as you normally would. I've only tested this for third person controller so far (but I see no reason why it wouldn't work for first person arms as well). If someone else has a better solution, please let me know. I've only been working with Unity for a couple weeks so this probably isn't going to be the most efficient way.
I created the attached script (which is very basic) but it seems to do the job. You create clothing items like you would other items, but leave the pre-fab as None when creating it using the UCC Item-->New Item. Just update the prefab by adding this script to the newly created prefab and set the UMA wardrobe recipe and slot name. If you need to hide meshes, you just do it on the UMA recipe as you normally would. I've only tested this for third person controller so far (but I see no reason why it wouldn't work for first person arms as well). If someone else has a better solution, please let me know. I've only been working with Unity for a couple weeks so this probably isn't going to be the most efficient way.