Attachments in mails sent via App Engine not readable on every mail client/ device

I'm using App Engine with Python. My application basically sends vcards (.vcf) by email when users request it.

Indeed, files with .vcf extension are supported by App Engine. I use the mail API to send them as attachment. Before, I stored them as db.Blob().

Problem:

Most of the time, Blackberry users cannot read the vcards sent as attachments by my application. At the bottom of the mail, it displays: "application/X-rimdeviceAddress Book:" and when you click on the file, it says: "This type of attachment cannot be opened on your device".

Exception:

A blackberry that receives a vcard serialized from a Blackberry can open it.

Fortunately, it perfectly works on the iPhone and (most of the time) on Android phones.

As vcards serialized from a Blackberry can be correctly opened by Blackberry users, I guess I'm doing something wrong during the storage and/ or the mail dispatc开发者_StackOverflow中文版h. Or maybe, the MIME type is not correctly set by App Engine methods...

Can someone give a few leads to investigate this pretty annoying problem (I was expecting a pretty big user base on Blackberry phones...)?

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Obviously as I mentioned on my comment above:
- it has nothing to do with Google App Engine
- some devices are just not able to read vcards in format 3.0

But I haven't found a good parser/ converter so far (from vcard 3.0 to vcard 2.1 in python) so if anyone knows one, please let me know. Otherwise, I'll have to build it myself...

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What is the code you are generating the vcard with? if I send a vcard from my blackberry device to an e-mail (opening it on a PC)

if I inspect the code with Notepad++

I spot the diffrents:

   X-SALUTATION:Mr/Miss
        X-HomeAddress1:HomeAddressStreet
        X-HomeAddress2:
        X-HomeCity:HomeAddressCity
        X-HomeState/Prov:HomeAddressStateProvince
        X-HomeZIP/PostalCode:1234 AA
        X-HomeCountry:HomeAddressCountry
        X-URL:http://www.url.com

How do you mentioned these lines in your Generate code?