How program sam3x8c or SAM4S8C via adruino ide

Hello,
i'd like design my own board. But sam3x8e are expensive and availability is terrible. But sam3x8c is cheaper and more accessible (SAM4S8C is even cheaper) . I found, that in IDE are integrated sam3x8c and SAM4S8C libraries, but there isn't board in board manager for compile code. Has someone experience with that?

@silas15, Were you able to get Arduiono IDE working for SAM3xC? We are also looking at using SAM3x8C