Color code problem

Hello.
I have this code:

colors = [0xFFCC00, 0xFFFF00];
alphas = [100, 100];
ratios = [0, 0xFF];
matrix = {a:100, b:20, c:5, d:100, e:0, f:10, g:100, h:10, i:5};
beginGradientFill("linear", colors, alphas, ratios, matrix);

I use it to fill a clip with a gradient color.
I want the second color (in first line) to be taken from a variable.
I tried:

my_color = "0x"+"FFFFCC";
colors = [0xFFCC00, my_color];
alphas = [100, 100];
ratios = [0, 0xFF];
matrix = {a:100, b:20, c:5, d:100, e:0, f:10, g:100, h:10, i:5};
beginGradientFill("linear", colors, alphas, ratios, matrix);

It doesnt work, it doesn't read the variable as a color and the color it sets is black.
Anyone knows how the color code should be composed so that I can have that color code taken from a variable?

Thank you.
- Adrian.