Hi,
That feature is no available in HikaShop 2.4 ; it is possible thanks to some view override to implement it (there is one or two threads which talk about it).
But we are working on a re-factoring of the checkout system and that new checkout will allow that.
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.