Pretty sure your standard soxhlet extractor doesn't work properly with vacuum but it's been ages since I used one so I'm not positive. The condenser at the top is open to atmosphere during normal operation.
If you are going to use ethanol then I'd just do it like QWISO. Those little cups in the extractor don't hold a lot of plant material and they would extract a lot of stuff you don't want in good oil anyways. I got at least a pound of sugar trim to get done here soon to make way for the new batch.
Google should be more help figuring this one out.