Filename is not embedded when using redirection

[feitao]

Hi,

My environment is Windows XP, gpg 1.4.2.2. I just found out that the
following are different:
1) gpg -o a.gpg -e a.txt
2) gpg -e < a.txt > a.gpg

When using -o, the gpg file embeds the original filename, thus
  gpg --use-embedded-filenmae a.gpg 
is valid. However, 2) does not embed the filename, and
  gpg --use-embedded-filenmae a.gpg
prints to stdout. 

My question is how I can embed the filename using Method 2 (< >)? The reason
I hate Method 1 (-o) is that it fails for large (~5G) files in Windows XP.

Thanks a lot!
Fei