Sending Long SQL to Sybase's Stored Procedure using 3+ variables

Can anyone help me to solve the following problem?
By some reasons I need to execute SELECT statement using stored procedure and through VB code or batch files,
but I need to cut it (statement) onto 3+
pieces because of the length (>>700 symbols).
Then they should be concatenated together into the sp and executed.
Example:
' Given in VB:
Sql="SELECT * FROM Tbl_A" (of course it's short here)

'cutting to 3 parts:
sA="SELECT"
sA=" * FROM "
sA=" Tbl_A"


I need sp something like this:
create proc sp_execute_sql
(
@a char(250),
@b char(250),
@c char(250)
)
as
/* and then execute query */
/* "SELECT * FROM Tbl_A" */

/* I now how to do it in MS SQL Server but it doesn't work in Sybase */