You need to use the UTF-8 format of the character. For conversion between Unicode and UTF-8, see In your case, the bullet character 0xB7 is c2 b7, so the text command would be:

utf8 on
t “\xc2\xb7” 100 100

Here’s a handy online conversion utility:

There are probably formulas to work these out in your application as well. Here is more detail than you might want: