[Qt-interest] Convert double to 1040,2e-9 value

[Matthias Pospiech]

I am looking for a way to convert a double to a QString with Scientific 
notation, but not as
1,0402e-6, but
1040,2e-9

So I want to define the digits before the decimal separator.

I know that I can set the option 'g' which takes the exponential away if 
the magnitate is below some value.
But I would like to be able to define it on my own.

Any chance to do that?