Create Type Problem

Hi
   I am newbie so this problem may be too simple to be asked.please help me if
any new thing to be added in following:

I want to use user defined data type in User_Type(n) way....

I created data type IndChar The c functions are:
/* Definaton of Data Type) */

typedef struct IndChar
{
    int32 len;
    char c_in_str[1];
}IndChar;

then i defined input & output functions.

Input: Datum indcharin(PG_FUNCTION_ARGS);
Output: Datum indcharout(PG_FUNCTION_ARGS);

then i created a function of the same name(i.e. IndChar) as
Datum indchar(PG_FUNCTION_ARGS);//for applying indchar(n) form i.e.fixed length
and i created it using:

create function indchar(IndChar, integer) returns IndChar
language C as 'Path for indchar.so file'
immutable strict;

after these i created data type using:
create type indchar
(input = indcharin,
output = indcharout,
internallength = variable,
storage = extended);

the type is created...

when i use it in Creating Table:

create table temp
(name IndChar(20));

it gives error at character '( '.....
please tell me why it is giving such error...
if some steps needed to alter or add tell me...
thanx in advance
Vinay jain