I'm in the UK. I use IMAP for free without any Asia workaround. I'm not sure why this is causing so many problems for people. What I did
1) log in to yahoo mail on a computer
2) in the top right corner of the screen there is the options Your Mobile | Options | Help
3) click on "your mobile"
4) It will ask you to confirm your mail password
5) Will oask for your phone type, number and handset
6) Will tell you mail app is not supported and gives you the following settings for setting it up with the HTC mail app
Encryption: none
Mailbox/Account: (this will be a long number DIFFERENT to your normal email)@yahoo.com
Password: (A mixture of letters and numbers DIFFERENT to your normal log on)
Outgoing SMTP Server: smtp.mobile.mail.yahoo.co.uk
Ougoing SMTP Port: 2525
Alternative SMTP Port: 25
E-mail address: (this will be a long number DIFFERENT to your normal email)@yahoo.com
Receive/Get: choose only heading or heading & text
From: your name (optional)
Signature: your signature (optional)
Copy outgoing: off/no (optional)
Along with various other info about IMAP etc
Make sure you use the email address and password given here, not your normal one. Don't worry, it all works out in the app and sends and receives as your normal email address
This method works for me, it's free, and I also have 2 other email accounts set up with HTC mail app
Hope this helps