stugpanzer, I have it stored next to the house and isn't an issue. You just give them a call and tell them it's in storage. They cancel full-coverage and just keep the fire and theft coverage. Will refund you the difference in premium. When you want to use it, again a phone call and they will bill you for the additional coverage when it's added back on (out of storage).
Double check with them on how many times a year you can do this and what the length of time it must be in storage or out of. I'm not sure as it hasn't been an issue for us.
Ours is in storage about 5 months of the year and saves us approx. $200 on our premium versus just having full coverage all year.