How to manually set z-axis values in a 3d plot?

I'm plotting an hemisphere with

radius = 5;
Height = 0.2;
SphericalPlot3D[ radius, { θ, 0, π/2}, { ϕ, 0, 2 π},
BoxRatios -> { 1, 1, ((0.5 Height)/(radius) + 0.03)}]


and I'm using BoxRatios to flatten the hemisphere so that it has a "height" of 0.2.
Is it possible to manually write/show the $z$-axis values so the visible range is not { 0, radius}
but { 0, 0.2}?

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Why not just plot the ellipsoid? SphericalPlot3D[h r/Sqrt[r^2 Cos[θ]^2 + h^2 Sin[θ]^2], {θ, 0, π/2}, {ϕ, 0, 2 π}] – Simon Woods Apr 14 '14 at 16:09
@SimonWoods: thank you, what you've written is very interessing. I don't know much about formulas with polar coordinates, that's why I can't use well SphericalPlot3D...is there a site where they're all listed? So that I can learn more... – Lory Lory Apr 15 '14 at 7:55
@Kuba : yes, I've just confirmed the answers. They're what I need. No matter if it looks flattened, it's more important to show certain values on the z-axis...I know I was asking for "strange" things...but it's the first time I've approached to mathematica and I'm making a mess! thank you anyway – Lory Lory Apr 15 '14 at 7:58
@LoryLory ok, thank you ;) – Kuba Apr 15 '14 at 8:02
@LoryLory, MathWorld is quite good for that kind of thing, there is also Wikipedia of course. – Simon Woods Apr 15 '14 at 9:10

If I understand you correctly you want to show the label "0.2" at the $z$-value 5.
The option Ticks allows you to do this. Here is an example:
 Plot3D[ 5 Sin[x y], { x, 0, π}, { y, 0, π},