my setup is
stockable custom fields
customfieldsforall
so i add a parent product with childs with the above custom fields
on export i set to export only childs
everything ok on the export
i have set on my template the custom_title custom_value custom_param
but the only field that has values of this is the custom_title
https://men2.demo123.gr/skroutz.xml
the param or the value is empty
on backend i see the child product with that filed with value
http://prntscr.com/vvbnjm
i attach the log file
please for your help