Hi,
To do so, you will have to edit the "invoice" of the plugin "attach invoice" and modify the PHP/HTML to add a new line for the shipping tax and also to remove the price of the shipping tax from the global tax line.
Depending if you have the "detailed taxes" or not, the required code can be more or less complex.
Related thread (for edit "attach invoice" invoice)
www.hikashop.com/forum/integrations/883230-pdf-plugin.html
Regards,
Jerome - Obsidev.com
HikaMarket & HikaSerial developer / HikaShop core dev team.
Also helping the HikaShop support team when having some time or couldn't sleep.
By the way, do not send me private message, use the "contact us" form instead.