private mib definition problem

[Chunmei Dai(CD)]

i define private mib files. 1.I want a 64 bit INTEGER as a table’s index. Then I use SYNTAX  “Counter64” as this table’s index 2.complie this mib file using tool “adventnet simulation toolkit”. This tool give me following message:      ERR-162              The objects having the syntax Counter32 or Counter64,                    must not be specified in an INDEX clause.   My question is :why I cann’t using SYNTAX “Counter64” as a table’s index, if cann’t using it ,which syntax I can use?   thanks   Chunmei