I take you are trying to put some stuff on a web page using the IPA?
That's sort of tricky. When you talk about "SILManuscriptIPA", I assume you're talking about an actual font, like Times New Roman and Arial. What are you doing -- just copying and pasting the text into an HTML file and wondering why it doesn't show up properly on other people's computers?
There's an explanation for that. HTML is just plain text with tags embedded in it which tell the browser how to format the text -- nothing more. When an HTML file specifies the font Verdana, that font is not actually downloaded with the HTML file. Instead, the HTML tells the browser to look for the Verdana font and use that. If Verdana is not installed on the computer, the browser has to use a different font.
In this specific case, I (and, I expect, most people) don't have SILManuscriptIPA installed on my system. So when it comes to the bit that you specify SILManuscriptIPA for, my browser can't find it; it uses the default, which is Times New Roman. I see this: Çiù«xt«r ÈAkl«
Basically, computers don't understand text and fonts. When the computer is called on to display some text, it doesn't think, "Ah, here we need something that looks like an upside-down lowercase 'e'"; instead, it thinks, "Ah, here we need character number 601".
Luckily, help (of sorts) is at hand.
These days, many people have operating systems and browsers that will cope with the Unicode character set. Most of those will have the character set Lucida Sans Unicode installed. That character set includes most of the extra symbols you need for the International Phonetic Alphabet.
If you have the Character Map on your system, you should find it in the Accessories program group under "System tools". Start it up, and select Lucida Sans Unicode. You can scroll down the list; if you click on a character, you will see a magnified image and, on the status bar at the bottom, a description complete with a code; for example U+0256.
That code is what you need. If you work directly in HTML, you can specify that particular character by using an entity: simply type &#x, followed by the code without the "U+", then a semicolon; like this:
If you specify Lucida Sans Unicode for that, you (and anyone else with Lucida Sans Unicode installed) should see the IPA symbol for a schwa when you open the file in a browser.
The code is in hexadecimal, which uses 16 symbols from 0 to 9, then A to F. The IPA extensions are between 250 and 2E9 on the character map.
So, for "Hello", you need to type:
If you have Lucida Sans Unicode installed, you should see it in all its glory here:
<font face="lucida sans unicode">
(I hope this works)