It most certainly can be done! If you want to check it out, I made a thread (Day 1: from inside to outside pottying using a bell.). I don't know if you want to use a bell or not, but you don't have to. But, I didn't want my yorkie and chihuahua to potty inside on the potty pads anymore so I decided to start them on going potty outside. They were doing ok with the pads, but were still having accidents. It is VERY helpful to get them used to a potty command. I say "go potty" for pee and "go poop" for poo. They have had that down for a while. I also wanted them to only go outside. No more potty pads for us. I did it cold turkey. I took up the puppy pads and outside they went. I did however put the used potty pad outside for the first week so they knew they needed to go outside to get to the pad. Snow, ice, mud, rain and wind. They went outside. I took them out every 30 min for the first day and I changed it to every hour, which I am still doing now. When they went potty, PRAISE, PRAISE AND MORE PRAISE and a yummy treat. Now, what I did in the house was look for signs they needed to go. Sniffing around, heading toward where the pad used to be, circling etc, and out they went. From the day I started, they have had 1 accident each.
They actually love going outside to potty. I am so glad I decided to train them to potty outside. And in the bad weather, they will potty faster so they can come inside quicker.
I thought it would be the opposite and they would take forever, but they surprised me. They do give me signs now that they need to go outside. What they do is go to the door and they start pacing. I open the door and they go potty. I hope my information helps you out.