Delete key from OpenPGP card?

[Nguyễn Hồng Quân]

Hello,

I'm implementing "delete key" in OpenSC for OpenPGP card.
To delete authentication key, for example, I think I have to empty these
DOs:
- 00C9, containing fingerprint for the key
- 00D0, containing creation time for the key
and rewrite the Extended header list with 00DB command.

However, I failed to empty 00C9. I tried these APDU:
1. 00 DA 00 C9
Return error 6700 (Wrong length)
2. 00 DA 00 C9 00
Return error 6400 (Execution error)

The 1st form, I tried with normal DO, like 005B, and succeeded.
The 2nd form, I referenced
https://gitorious.org/gnuk/gnuk/blobs/master/tool/gnuk_remove_keys.py#line98
(This script is for Gnuk card and success with Gnuk).

Why none of these APDU work with OpenPGP card? What is the correct APDU
for OpenPGP?

-- 
Regards,
Quân

Y!IM: ng_hquan_vn
GTalk: ng.hong.quan