Keep %xsd.double "as is"

Hello!

We have an integration that reads a file from labresults and needs to be transformed into another file format.

The transformation and incoming file correlate against a schema. In that schema there is a type declared as %xsd.double.
As these values ​​are labresults, we are not allowed to change the expression of the value in any way. For example, 1.0 must not become 1. And 2 must not be written as 2.0. As well as 0.3 must not be written as .3 and so on.
I am not allowed to change the type in the schema to %String. I am not allowed to change anything in the schema at all.

I've tried and tested with FNumber and other things but none transform the value "as is". Greatful  fortips! 

Regards,
Michael Lundberg