Have you tried this Dutch site www.ryksargyf.org It is a Dutch site with a lot of information on birth-dates, dates of death, marriages. You might be able to go back a few more generations. If you need any help with the translations, feel free to aks me. You also may want to try in Yahoo-groups "Friesland genealogie". You can ask your questions in English. You might find someone there who has done research into that family.