Hi,
I am trying to create a custom function using function modeler in ION Graphical Mapper. I am not able to map source to target, as I see that option on the right click disabled. Attaching screenshot here. Please suggest if there is any step wrong or missing or kindly let me know how to model a custom function.

In the function code I have written '<xsl:value-of select="xs:anyURI($FileName)"/>'.
The agenda of the function is to cast a string to anyURI format so that it can be mapped to an anyURI field.
Thanks in Advance.
Regards,
Ridhima