Я не вижу проблем с этим Base64, у вас есть данные в формате $ LB.
USER>s b64="AgEDATECAQgBU2luZ2xlBATD+QQEkH4EBCD9BAQcAgIEBQE2RE4CAQIBAgECAQIBYwEJAWFmd2V6aWcCASoBX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fXwIBFQFIb2dlIEhvbmRzdHJhYXQgMTE1EwE3NDEzIENFLCBERVZFTlRFUgIBBQExQVMFATVBQwYBMzhHQg0BNjM4ODEsMzU4NjM="
USER>s data=$system.Encryption.Base64Decode(b64)
USER>zw data
data=$lb("","1","","Single",63939,32400,64800,540,0,"6DN","","","","","",$lb("afwezig","","________________________________________","","Hoge Hondstraat 115","7413 CE, DEVENTER",""),"1AS","5AC","38GB","63881,35863")