* Pope showing early on he will do things differently
* Shunned papal limousine on night of election, paid hotel bill
* Vatican not sure if he will use prepared remarks at Mass
By Philip Pullella
VATICAN CITY, March 14 (Reuters) - The Vatican, an age-old institution used to having almost everything done by the book, is bracing for the unscripted papacy.
In less than 24 hours after he became the first non-European pope in some 1,300 years, Francis seemed to break more rules than his predecessor did in eight years.
"We are going to have to get used to a new way of doing things," said Father Tom Rosica, an amiable Canadian priest who runs a Catholic television station in Canada and was drafted to Rome to help with the media influx during the papal transition.
Indeed, the first words out of Francis' mouth after he became pope sent a signal that things would be different.
He did not start by using the customary "Praised be Jesus Christ" or "Dear brothers and sisters", but employed a much more familiar and inviting "Buona Sera" - good evening in Italian - to address drenched crowds in a rain-swept St. Peter's Square.
"I was stunned by what happened last night. I didn't expect a pontificate to begin with 'Buona Sera,'" Rosica said.
On the morning after his election, the Vatican was scrambling to meet the needs of a new-style papacy.
"We have to have patience, we are starting something new. There are a lot of things we don't know yet," said Father Federico Lombardi, the chief Vatican spokesman, as he faced a barrage of reporters' questions about what to expect.
The answer is probably: expect the unexpected.
Even before he delighted the crowds with his unorthodox style on the balcony of St. Peter's Basilica, Francis give a hint of a new style to his fellow cardinals.
NO THRONE, THANK YOU
While he was still in the Sistine Chapel, his aides had set up a throne-like chair on a platform for him to sit on while the cardinals pledged their obedience one at a time.
Instead, he came down to their lower level and remained standing while they each greeted him.
Less than an hour later, he shunned the papal limousine that was waiting to take him to a Vatican residence for a meal.
"And as the last bus pulls up, guess who gets off? It's Pope Francis. I guess he told the driver 'That's OK, I'll just go with the boys,'" said Cardinal Timothy Dolan of New York.
The only difference between him and the cardinals was that he was no longer wearing their red robes, but white.
There was more unorthodox papal behaviour on Thursday morning when Francis returned to the Church-run residence where he had checked in as a cardinal for the conclave. He insisted on paying his hotel bill, despite now being the boss.
"He wanted to get his luggage and the bags. He had left everything there," a Vatican spokesman told a news briefing.
"He then stopped in the office, greeted everyone and decided to pay the bill for the room ... because he was concerned about giving a good example of what priests and bishops should do."
The spokesman did not disclose the amount of the bill.
Jorge Bergoglio brought a reputation for frugality from his native Argentina, and is the first pope to take the name of St. Francis of Assisi, who preached the virtue of living in poverty. The name is seen as a gesture of solidarity with the poor.
While his predecessor Pope Benedict almost never made unprepared remarks, the Vatican said it had no text of a homily the pope was to read later that day at a Mass: "We just don't know what he is going to do yet," Lombardi said.
Reporters asked: Will he travel? And where to?
Lombardi said he expected the pope to visit his Argentine homeland eventually and almost definitely to go to Brazil in July for World Youth Day, a Catholic festival that takes place every two years in a different city.
Asked about how Vatican security would respond to a pope who did things differently, making decisions at the last minute, Lombardi said: "That's a good question. Vatican security are at the service of the pope and will have to adapt themselves to the pastoral style that the pope will use," he said.
"A pope's personal style has to be respected," he added. (Reporting By Philip Pullella; Editing by Peter Graff)