Here's what I want to achieve with TWS but couldn't find a solution. (I realize my trading scheme may seem weird): Before going to bed, I want to place a sell (short) limit order on ES. If ES doesn't hit my limit price overnight, I want the order to expire at 8AM ET. This is easy to do with the time conditional order. Now, this is the hard part. If the sell order is filled, I want an automatic buy (cover) limit order placed effective at 9:30AM ET. Again, the second order itself is easy with the time conditional order. But how do I attach the 2nd order to the first order? I have tried "attaching" but TWS rejects the attached order saying "conditional order must be limit or market". The message seems incorrect because it is in fact a limit order. Anyhow, TWS just doesn't seem to like a conditional order as an attached order. Anyone with an idea?