You can use your MobilityPlus charge card in Belgium and abroad anyway. There are no restrictions on roaming (use abroad). But being able to charge doesn’t mean it’s allowed. This will depend on your employer.
You will find the provisions for using the charge card abroad in your employer’s Car Policy. Still confused? If you have further questions, ask your employer to avoid misunderstandings. Rule of thumb: if you were not allowed to fill up with petrol or diesel abroad, chances are you are not allowed to ‘fill up’ with electricity either.