Working memory includes the ability to store things in short-term memory, but is probably best described as the ability to manipulate things in short-term memory. It is believed that auditory and visual wm are somewhat independent processes, so sometimes you will see disparities there. Very high cog persons, especially with good processing speed, may be able to compensate for lower wm by rapidly transferring data to long-term memory, which may be what you are seeing as good memory skills.

...pronounced like the long vowel and first letter of the alphabet...