It might solve this particular issue, but in general moving away from XML::Simple will serve you better long term. The module is conceptually broken. It treats XML as being basically weird-looking JSON. But XML's data model is entirely different than JSON's. Not going to get into a debate about which data model is better, but treating them the same is like writing flight-planning software that will only generate flight routes that follow highways.
Somebody else recommended XML::Rules, which is probably the easiest thing to transition to from XML::Simple. It still allows you to treat the XML like glorified JSON, but requires you to give it rules about how to translate between the models, with some sane defaults.
The other thing I'd recommend looking at is XML::LibXML, which provides a full DOM API for XML, which will be pretty familiar if you've done any client-side Javascript programming.