Thanks for the ideas, but for my unluck none of the working. It seems that dafault the groupwise working with HTML format and when i change it to clear text i can use the current windows encryption option but it should be better to be a button on the client.
When i tried Tom's suggestion i received connot'4 load module message and when i tried to make seach for pgpgw.dll it closed without result.
If you have any other idea don't hesitate to share it with me.