How To Create Reference For Composite Key

Hi All,
 
Can anyone tell me how to create a reference for composite key.
For ex, I have created tblEmp table successfully.

create tblEmp
(
 empId varchar(100),
 RegId varchar(100), 
 empname varchar(100),
constraint pk_add
primary key(empId, RegId) 
) 
 
 And now, I am going to create another table which references the composite key.
create table tblAccount
(
  acctId varchar(100) primary key,
  empId varchar(100) references tblEmp(empId),
  RegId varchar(100) references tblEmp(RegId)
 
) 
 
But it gives error like
 
Server: Msg 1776, Level 16, State 1, Line 1
There are no primary or candidate keys in the referenced table 'tblEmp' that match the referencing column list in the foreign key 'FK__tbl'.
Server: Msg 1750, Level 16, State 1, Line 1
Could not create constraint. See previous errors.
 
 Could anyone please let me know how to create reference for composite key.
 
Thanks in advance,
Arun.