Ismael, a French Under-21 player, agreed to move to Palace on a four- and-a-half year contract from Strasbourg, even though he admitted knowing little about the Eagles.
Speaking through an interpreter, he said: "I like the English game, with the contact, and I knew the name of Crystal Palace. I am pleased to play for a club in the capital and it will be good for me and my family. It is an exciting challenge to play with Tomas Brolin, Michele Padovano and Attilio Lombardo. I will enjoy playing in the Premiership because of the atmosphere and the fans."
However, French transfer regulations mean Ismael will not be available to play at Oakwell on Saturday, but should be set for his debut in next Saturday's FA Cup fourth-round tie at home to Leicester.
Brolin, meanwhile, will be ready to face Barnsley, after his two-week training period with Palace whetted his appetite for the Premiership again.
The Swedish striker said: "They believe in me here and that's a good thing to have when you go out on to the pitch. I know what I can do when people trust in me and try to help me. I'm keen to stay because it's a very nice club with nice players and I can be a success here."
Manchester United's solicitor Maurice Watkins claimed he was "bemused" by reports that the club have agreed a pounds 50m sponsorship deal with Ford.
Watkins claimed the club were not even in discussions with the company, which currently backs the Spanish First Division side Valencia. A spokeswoman for Ford admitted they were interested in football sponsorship, but denied reports of any future agreement with United.
Aston Villa's Yugoslav international Sasa Curcic is in Istanbul for transfer talks with Besiktas. Curcic has been unsettled at Villa Park and has reportedly agreed a pounds 1m deal with John Toshack's side. Villa paid pounds 4.5m for Curcic from Bolton 18 months ago.
Villa will, however, welcome back Dwight Yorke, who has been given permission by Trinidad and Tobago to leave international duty at the Gold Cup in America to play in the fourth-round FA Cup tie with West Bromwich on 24 January.
Scotland's 40 league clubs will hold a special general meeting early next month to decide if they will support a breakaway move proposed by the Premier Division clubs, following a vote by the League management committee meeting yesterday.