internal class MyOracleDialect : NHibernate.Dialect.Oracle10gDialect
     {
         public MyOracleDialect()
         {
             RegisterFunction("packedString", new StandardSQLFunction("w_common.f_pack_str"));
             RegisterFunction("concat", new StandardSQLFunction("concat"));
         }
     }

IList<Part> parts = 
     session.CreateQuery("from Part p where p.CompactName like concat(packedString(:p), '%')")
               .SetParameter("p", "ЗКС15.")
               .List<Part>();

 SELECT PART0_.ID            AS ID1_,
        PART0_.RN_ISPOB      AS RN2_1_,
        PART0_.OBOZN         AS OBOZN1_,
        PART0_.NAIM          AS NAIM1_,
        PART0_.PACK_OBOZN    AS PACK5_1_,
        PART0_.MODEOFEXECUTE AS MODEOFEX6_1_,
        PART0_.ORDERNAME     AS ORDERNAME1_,
        PART0_.ROUTE         AS ROUTE1_
   FROM W_ZEX003.MV_PART PART0_
  WHERE PART0_.PACK_OBOZN LIKE CONCAT(W_COMMON.F_PACK_STR(:P0), '%');
 :P0 = '??????15.' [ TYPE :STRING(6) ]