As your link describes, the problem is that the typical microSD module does not release the MISO line when it is not selected by CS. So it interferes with the other SPI device when it tries to send data to the processor. In electronics terms, the MISO line is sent through the voltage shifter, and is therefore always either high or low when it really should be HZ (not connected). The Adafruit modules do this correctly, which means they connect the SD card's output pin directly to the MISO header on the module, and bypass the level shifter. Then the SD card itself will tri-state MISO when its CS line is not asserted. The fix I use is shown below. You solder one wire, and cut one trace. With any luck, your module layout will be the same.
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