C# - Unable To Use Certain Fonts Programmatically?

I am trying to programatically create a bitmap with a specified font in ASP.Net. The idea is that the text, font name, size color etc. will be passed in from variables and a bitmap of the text using the font etc will be returned. However, I have been finding that I am only able to do so using the following code with certain fonts.

<div>
<%
string fontName = "Segoe Script"; //Change Font here
System.Drawing.Bitmap bmp = new System.Drawing.Bitmap(100, 100);
System.Drawing.Graphics graph = System.Drawing.Graphics.FromImage(bmp);

[Code]...

If I change the font name in the areas indicated by the comments to Arial or Verdana both the image and the label appear with the correct font. If however, I change the font name in both locations to something "Segoe Script" the Label will show up in Segoe Script but the image is in what looks like Arial.

Update:

Based on this question here I was able to get it working by using a PrivateFontCollection() and loading the font file like so.

<div>
<%
string TypeFaceName = "Segoe Script";
System.Drawing.Text.PrivateFontCollection fnts = new System.Drawing.Text.PrivateFontCollection();

[Code]....