This program [Key Manager] is genius! Pros: Very simple, intuitive, lightweight and cute. And it works! Cons: Haven't found anything yet. Summary: I was spending more then 4 hours in order to find a program which can replace Left, Right, Up, Down buttons with Alt+JKLI, that I think is very useful when programming or editing text. Most of the macros programs don't offer the possiblility of ramapping keys, others that offer just don't work!
Finally I found this program. Of course it has much more useful functions.
cnet.com, User reviews
Key Manager - Demo video
5. Emulation of a double click of the left mouse button
The example shows how a double click of the left mouse button is assigned to F1 and F2 with a 600 ms delay.