Apart from the information that is stored in the XML file by ITP itself, the model is also able to add custom information to it. To this end the function
FUNC TEXT add_user_xml (CONST TEXT key; CONST TEXT value)
is available. It will add key/value pair to the XML file. This pair is enclosed in an <itp:element> element, and contains <itp:key> and <itp:value> elements for the value of key and value. All elements added with this function will be collected under a <itp:userdata> element.
If the function is called repeatedly with the same key name, the later values will overwrite the earlier ones. There will only be a single element with the name key present in the resulting XML file.
If ITP is not instructed to generate the XML file, this function will not produce any output, nor will it generate an error.