By 'proxy' table, I am assuming you mean that this is a Table in Sybase which maps to a remote table/view/procedure.
In DB2, if you want to access non-DB2 data sources natively (ie via SQL), then you need to use the Federation technology in Websphere Information Integrator, and using this, you can define remote servers (ie a Sybase databases), and nicknames (ie a Sybase Table). You can then access the data as if it were a local DB2 Table.
If you want to physically move the data from Sybase to DB2, then you have
many options, such as II above, export/import, etc., but I believe moving this scenario is more complex then a simple export/import.
There is an useful article on using II and Sybase:
Currently I am having MS Access linked to Sybase database. Could you please help me in creating the link between MS Access and DB2?
Secondly, regarding the proxy tables in Sybase - the Web Sphere Information Integrator will only send the request to Sybase for Stored Procedures' resultset which is nothing but the "existing table" (Proxy table).
But, what if Sybase is not there? Can we have a total substitute of those proxy tables in DB2 itself?