[MetaKit] SortOn a string property but case insensitively !

[Aurélien Hugelé]

hi, i'm new to MK, but still i achieved to use it for my project :)
the only problem i encounter is when i want to sort my view by First 
Name and lastName.
i use SortOn(firstname,lastname), which is fast. But unfortunately, if 
i have 3 people called
Aabab martin, toto martin and Zozo martin, the SortOn() returns me, in 
this "wrong" order:
Aabab martin
Zozo martin
toto martin

because the sort is case sensitive...

how can i achieve caseInsensitiveness ?

thanks all