No. We do not know which model the 2 piece Southbeach is. And even if it is not KR808D-1 (apparently not) it could be KR808D-2 (see AzSmokeFree for cartos for that) or E8 (only place to buy blank cartos might be China)
re refillable cartos - that means soft-caps - ones with a soft cap on the mouth end - the cap comes off easily and you refill by dripping down the inner sides of the carto into the stuffing, slowly, while rotating to fill on all sides. Rip-off rebranders do not sell blank cartomizers and generally use the harder to refill hard caps (or worse, glued on hard caps) because they don't want the user to refill them. There are tricks to fill hardcaps, like using the carto condoms (if the rebrander even put these clear soft caps on the ends of prefilled cartos) - some use the condoms to force juice into the carto, spin somehow to distribute it, blow out any that got into the air hole. I have not done this so if you want to know more about it I recommend you make a new thread and ask int he title.
There are also more exotic cartos for popular models (like 510) with a reservoir that needs to be filled with a flexible or other syringe.
Re South Beach - I think if you cannot get a for-sure identification and a reasonable source of parts then you need to just buy something else. But first give AZSMokeFree.com a try - they are the only non-ripoff vendor I know of who sells KR808D-2 parts (as opposed to KR808D-1 which they also sell). They only seem to sell filled KR808D-2 cartos though and I don't know if they are soft caps so ask them - they do sell a curved syringe which could be helpful for filling soft-caps. They may even know if South beach uses those KR808D-2 carts. And if so, ask them about how to fill them.
The Better Way To Smoke - KR808D-2 Cartomizers
Note - you can only refill cartos some random limited number of times before they die or you singe the stuffing. Running them all the way to dry shortens their life. But they also are considered disposable so the internal atty could just die even if you treat them properly.
If you cannot find parts for Southbeach but like cartomizers then consider getting a KR808D-1 instead (basic kits at various vendors, fancier colors etc at Vapor4Life.com and Bloogplanet.com)