The brother of Sinn Fein president Gerry Adams is to take his extradition fight to the Republic's highest court over claims that a letter was being withheld from his legal team.
Liam Adams is wanted in Northern Ireland for the alleged rape and indecent assault of his daughter.
During a brief hearing in Dublin's High Court Mr Adam's barrister Maeve Corbett (Junior Counsel) said they were appealing to the Supreme Court to have the letter between the Crown Prosecution Service in Belfast and authorities in Dublin disclosed to them.
Mr Justice Michael Peart adjourned the case until October 6.
Mr Adams, who handed himself into the Garda in the Irish Republic last March, had been excused from attending court and was not present on Wednesday. He has been remanded on continuing bail.
At an earlier hearing Mr Adams' senior counsel Michael O'Higgins said it was necessary they saw the letter because if it suggested any shortcomings in the European Arrest Warrant that echoed their own concerns then it would help their case.
Investigators in Belfast want to question Mr Adams on 18 charges of sexual abuse, including rape, indecent assault and gross indecency, against his daughter Aine Tyrell, who waived her right to anonymity last December.
The alleged offences date from March 1977 to March 1983.
Mr Adams has also asked for legal aid to cover the costs of transcribing reports from Belfast media outlets about his sex abuse charges.