can't choose first generic child variant of the list

can't choose first generic child variant of the list

i finally set a 2 level child product cart.
the problem is that i had to create fake child products with property
"stock" set to zero (so can't be add to cart) and also give them
ordering=1 (i gave 2,3,4,... to the other real products) so that the fake
products are shown first in the dropdown list.
this is because i noticed that first elements of dropdown list can't be
selected!
example: for generic child variant "color" i created child products called
"choose a color","black","white","green",... the "choose a color" is shown
first in the list so it doesn't matter if it can't be selected when i
reach the page where i have to select the color!
is that a usual problem workaround or it can be done in a proper way???
thanks