Serial Data Transmission of 11 bit data in 8051

Hi I am in big problem, I have to transmit 300 data packets each 11 bit in size serially to 8051 or DS89C430 microcontroller and multiply each with another data of 11 bit stored in ROM. The multiplication goes on for 300 times one by one and each product has to be added (adding up all the products) to the previous and stored in a temporary basis in RAM or Accumulator. But problem is that, during serial transmission the data goes to the SBUF (serial buffer register) first which is 8 bit in size and when fills then the flag is raised so that the data contained could be saved somewhere.

Now my data packet is 11 bit in size but the register is 8 bit. How to then perform the above task. Also I dont want to use any 16 bit controller.

Please help as soon as possible.

one option is:
in 8051 :divide your data into two chunks of 8+3
send it in two packets.
on the other end(receiving end) you must have the sw to properly assemble the two chunks into 11bit .