Hi,
The paypal plugin will list the product option if you do not group the options with the main product (in your HIkaShop configuration).
After that I don't really know how you want to display the product options in paypal but you can edit the paypal plugin in order to change how the products are send ; just by modifying the line
$group = $config->get('group_options',0);
to no read the configuration and force the setting to "0".
Please note that if you modify the paypal plugin, you will need to re-modify each time you will update HikaShop.
If you want to keep your modification, the best will be to create (duplicate) the paypal plugin into a new plugin to be sure that you're plugin won't be update during updates.
Regards,