The tube used for plumbing the cold water supply to a toilet is available in plastic, and it's the perfect size for fitting the Panasonic condensor microphones, including the WM-60AY. These tubes are about 20" (1/2 meter) long and work very well for this purpose. You can pick them up at just about any hardware supply store.

The capsule can be pressed in and it fits in snugly. Run a shielded microphone cable up through the tube and solder it to the tabs on the microphone so that the solder joints do not extend wider than the diameter of the capsule. Press the microphone down into the tube a little bit so that it is held firmly.

This makes a neat little measurement boom. One end is the microphone and boom, and the other end is shielded cable to RCA plug.