You will want to use the schematic of Figure 2 but disconnect DACOUT and R6 and drive the FB pin with your own external DAC. You'll want to select R5 and R8 according to the "Output and DAC Adjustments…
Question: How do I connect the SPI pins of the MAX 1932 when using an external DAC?
Answer: An external DAC can be connected to the chip via the following connections:
SCLK is connected to the serial…