Perl XML::Compile::Schema - can we write an actual 'NIL' string for a nillable value?

I'm using XML::Compile::Schema to generate schema-compliant XML. It has a feature where a nil value is represented by using the string 'NIL' as the node's value.

It seems that if we actually want the text NIL in a nillable node, it's not possible. Is there a way to achieve this?

I could write out NIL but the writer will change the & to & so that doesn't help.

It feels like a potential bug waiting to happen, as we are converting client provided data and fields with short 2 or 3 letter codes are not that uncommon. Is it possible to write such a value using the provided writer?