Fortunately, you can at least change it to UTF-8 in your PayPal preferences. But it's not easy to find. Here's how to do it.
Log into your PayPal account and click Profile to edit your profile. At the bottom of your Selling Preferences you will see Language Encoding. Click that. There will be a More Options button. Click that. Now change the Encoding to UTF-8 and click Save. If you leave the "Do you want to use same encoding..." option at the default Yes, you only have to change the encoding to UTF-8 in the top drop-down.
Here's what it should look like right before you click Save: