Racing Seats in my early Boxster Street Car

[M030]

I just got a great deal on a pair of Recaro Pole Position seats. I want to install them in my 1997 Boxster that is primarily a street car, but I also use it for autocross. I really need to find out what I'm going to do about seatbelts when I install my nice new racing seats. I guess this is only an issue because I do not want to install racing harnesses, and I've decided against deleting the SRS. So, what I'm asking you, is how to make normal, DOT 3pt safety belts work effectively with seats that were designed for racing harnesses? Some Porsches, like the early 996 GT3 and 993 RS have done so (successfully, I presume, as they were street legal and had racing seats w/o harnesses)