Running nested scripts with sqlplus via http

@test2

Hi,
in 11.2.0.3.

@test2 par1

test2.sql: prompt I am test2.sql invoked with param: &1


Now I run test.sql via http:

http://server:7778/sql/test.sql
SP2-0556: Invalid file name.


http://server:7778/sql/test2.sql
Enter value for 1: par

I am test2.sql invoked with param: par


Now i modify test.sql and remove the param

@test2


http://server:7778/sql/test.sql
Enter value for 1: par
I am test2.sql invoked with param: par


Why am I unable to use parameters in test.sql script and run it with http?