I want to solve numerically the nonlinear problem 

a*(diff(y(x), x, x))+2*(diff(y(x), x))+exp(y(x)) = 0, y(0) = 0, y(1) = 0

by defining my own method defined as 

y_n+1=y_n+2*h*(-2*y_n+2*ln(2/(1+x))-(1/2)*a)^2/(a*(-4*y_n+4*ln(2/(1+x))-a-h*(4*y_n-4*ln(2/(1+x))+a+x+1)/a))

where h is the step-size. Please help me by letting me know how can I do this using Maple 11.