If you have an IMC, it generally has two benefits:
1. It lifts certain restrictions that are placed on your vanilla UK PPL, including the "in sight surface" restriction.
2. It gives you the ability to fly in IMC conditions, outside controlled airspace.
Item 1 applies worldwide, but item 2 is UK-only.
So outside the UK you have to fly in VMC conditions. Those VMC conditions limits are defined on a per-country and per-airspace class (A-G) basis. But I'm not aware of any VMC condition in any class anywhere that allows you to fly in cloud. So any kind of cloud flying is forbidden. Also, mind that certain classes of airspace in some countries have an "in sight surface" requirement attached. In that case you still have to follow that requirement even though that requirement is lifted from your license.
So to descend through a cloud layer you have to find a hole. A hole which is actually big enough to satisfy the VMC conditions with regards to cloud clearance: Just the width of your wings may not satisfy VMC conditions unless those limits are just stated as 'clear of cloud'.
Or you rely on a bit of common sense and the fact that it'll be extremely hard for a prosecutor to successfully prosecute you for not maintaining VMC. (So don't put your "marginal VMC" flight on Youtube...)
Last edited by BackPacker; 31st May 2011 at 16:02.