Thanks for the comments

Andy, as Chuck said above, you can get that bloom from the REX support forums (you have to register to access it), there's a section called "freeware..." something like that. I got the set that is called "Sunlight". There are some preview screenshots in the topics.
The archive you download is complete: it contains the bloom module + settings + color palette. In my case, just three files I had to drop directly into the main FSX folder. Very easy, and fantastic results 8-)
A bit of warning though:
- the ENB bloom works ONLY in DirectX9 mode. It will also work in FS9, but it will not work in FSX if the DirectX10 option is enabled.
- the ENB bloom doesn't like the old video cards (but it was already working fine on an old GeForce 6800 GT, for example)
- the ENB bloom hates the very high AntiAliasing settings (16x and more).
- the ENB bloom will cause a big increase of the memory consumption of FSX, leading to potential "out of memory" errors. I could sole this on my computer by activating the virtual memory (swap file), which had been deactivated by myself a long time ago (I thought I had enough memory).