Question: eval and recalling part of a solution

hi!

two questions for the most expert among you:

question 1)

i want to evaluate a function A in a point identified by a number of variables that i have already numerically found from the solution of a sistem (let's say my solutions are S:={B=0.01, C=0.2, D:=0.3} ) but A also depends on another variable (Z) to which i want to assign a value

so i need to write eval(A,S) but also considering Z and it seems that eval(A,{S,Z=1}) doesn't work.

how do i tell maple to compute A considering both the solutions in S and Z=1?

question 2)

starting from the variables cited above, how do i tell maple to compute (a number of) A considering only B and C found in the solution S, and letting D going from 0 to 1?

Then i need to plot D going from 0 to 1 against the values found for A.

thanks!!!!

eleonora