Virtuemart plugin CSS override

[gbruzzo]

Dear All,

I am currently working on overriding a VM customfield plugin, called catproduct.

Joomla 3.4.3
VM 3.0.9

the folder structure, as expected, is

/plugins/vmcustom/catproduct/catproduct

the 'second' catproduct folder contains four folders, helper, js, css and tmpl.

to create an override I created folders structure vmcustom/catproduct in

/templates/[template_name]/html/

Thanks to user Jörg's instructions, I understand now I must copy the .php template (here called default.php) straight into

/templates/[template_name]/html/vmcustom/catproduct : So far so good, VM loads it.

The question is then : how does one override the plugin's own .css files? Tried to

- copy catproduct.css into

/templates/[template_name]/html/vmcustom/catproduct, with no success;

- create a folder called 'css' in the above, containing the css file. Again with no success.

could you please let me know if it is possible at all and if so, how?

Thank you all in advance for your time

Giacomo