Hi,
Regarding the documentation, the paypal standard plugin could be better.
This plugin redirect the customer to the paypal website. I think that, if you have a paypal advanced account, it will be possible to use it in the paypal website after redirection.
There is too many paypal solutions and the documentation does not explain clearly how integrate it so.. It is just speculation.
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.