Hello Manfred
And welcome to the forum, in reply to number 1 from my experiences, of paying for any item online, it all depends on the payment gateway as to what cards are accepted (not sure if the website owner can specify what cards visa, maestro etc are to be accepted, payment gateways allow website owners to accept cards), i live in southern ireland and i have a laser card with cirrus maestro enabled aswell, but it is completely useless on UK sites that do not accept laser cards as a payment even though it is maestro enabled, (Laser cards are the same as your bank debit cards) but it is ok on irish sites that do accept laser, i can not even use my laser card even though it is maestro enabled with paypal, even though paypal have offices in dublin i believe, correct me if i am wrong, if i want to use paypal i have to either use credit card or upload funds from my bank of ireland account,
on my own website i only use paypal as a way of accepting payments via a credit, debit card due to the cost of using a payment gateway, paypal works out a lot cheaper for me, i do have roman cart aswell but the free version for sending payment as cheques, postal order, bank tranfer
Number 2 George can answer
Hope my answer helps in some way to your first question, the above are my own general thoughts and experiences
Phil