Since you control both ends of the communication, the possibilities are wide & varied to solving a problem of this type. Here's one way to do it (pseudo code):
Sending side:
# data10bits is at least 16 bits wide.
byte1 = (data10bits >> 8) & 0x03;
byte2 = (data10bits & 0xff);
rfSend(byte1, BYTE);
rfSend(byte2, BYTE);
Receiving side:
# Again, data10bits is at least 16 bits.
byte1 = rfRecv(); # get a single byte
byte2 = rfRecv(); # get second byte
data10bits = (byte1 << 8) | byte2;
Adjust the endianness to taste.