Did you get the codes for the shop for v2? well if you didnt look at the Tamagotchi Codes part of Tamatalk. after you get the costume, go to your items and look for ''costume'' then once you find it press the middle button or b button. your tama (it has to be an adult) shoots up then comes back in the costume! to take it off you put your tama to sleep but pressing a+c on the clock screen. Hope i helped!
Here is how to get a panda costume on your connection v2:
Go to the shop and press A once and then press A three times really fast. The shop guy should look suprised. Then press CBAACABC and then you will see a panda and it says TRY IT! Go to your items and select the stuffed animal. Your tama will turn into the panda. At bedtime it takes the costume off and it dissapears from your list of items. I hope this info helped!