Hi,
You can the same user ids => You have the same user ids.
It means that you have to check that users are right imported with the same ids.
If not, you could have troubles with HikaShop users because the id for the joomla user will become wrong.
It that clearer ?
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.