I realize it's a bit late now, but for any other readers, this is much easier to manage if you break up your shorts into small orders. That way you can roll it all over gradually with a lot less extra BTS.
Is it all a single order coming due at once?
It was 3 separate order. Two small, one bigger.
They all come due within a day of the first one.
This is the worst thing I have come across in BitShares. How could this be? It seem it would be common sense to be able to cover, especially since the blockchain controls the collateral.
I do not know if you started this as a general concern thread or do you need a solution for just now.
1. Generally - This was done because BM feels the more collateral the safer system... at all costs. My total disagreement with that notion is well documented. At least he is softening his stands as was quoted above on this 'soft collateral' issue....
2. Practical - The way to do it (assuming you do not want to put new money in BTS) is to:
Borrow BTS from a friend; buy bitUSD, cover your shorts and return the loaned BTS from the collateral you will get back.
This works only if you have not lost too much and there are enough bitUSD for sell...Right now you will have to pay quite a premium for any bitUSD you want to buy, though.
Hope this helps....