Question: Integral over Dirac distribution

Hello,

I want to evaluate an integral over the Dirac function with basically the following assignments. (I had some troubles parsing here...) Then I want to plot function rho(epsilon). What I get is just an empty graph with nothing displayed although test has only values in the range -3...3. I am pretty new to maple and don't know how to compute this in another way.

> test(x,y,z) := .2686733768*x^2+.2686733768*z^2-.2178281566+.2686733768*y^2+(-1)*1.000000000*sqrt(7.218538340*10^18*x^4+1.443707668*10^19*x^2*z^2+(-1)*2.346720089*10^18*x^2+1.443707668*10^19*x^2*y^2+7.218538340*10^18*z^4+(-1)*2.346720089*10^18*z^2+1.443707668*10^19*y^2*z^2+4.463460439*10^17+(-1)*2.346720089*10^18*y^2+7.218538340*10^18*y^4)/10^10

> rho(epsilon) := (1/8)*(int(int(int(Dirac(epsilon-test(cos(kx), cos(ky), cos(kz))), kx = -Pi .. Pi), ky = -Pi .. Pi), kz = -Pi .. Pi))/Pi^3

>plot(rho(epsilon),epsilon=-3.0..3.0);

Thanks for your help.