If you are only seeing the issue on PayPal's site then it is probably not an issue within PowerStore itself. I tried with the example you posted and was not able to see the issue.
If it is information that comes from your form that is not showing correctly then you might try doing some encoding of the information before you send it to PayPal. If it is a direct post this may be more difficult to do. When you see this on the PayPal site what does the source for the bad characters look like?