To Execute or call SQL Stored Procedure in Axapta by code you can get hints from below code. You can also pass parameter with stored procedure in string format.
UserConnection Conn;
Statement Stmt;
str SqlStmt;
SqlSystem sqlSystem;
SqlStatementExecutePermission sqlPermission;
ResultSet resultSet;
str StrFromdate,StTodate;
StrFromdate =strFmt("2010-01-01");
StTodate =strFmt("2014-03-31");
sqlSystem =new SqlSystem();
SqlStmt =strFmt('Exec SP_StoredProc \'%1\',\'%2\'',StrFromdate,StTodate) ;
Conn =new UserConnection();
Stmt = Conn.createStatement();
sqlPermission =new SqlStatementExecutePermission(SqlStmt);
sqlPermission.assert();
Stmt.executeUpdate(SqlStmt);
CodeAccessPermission::revertAssert();