I havent done the 6.1 upgrade so cant comment if this solution will work for you. However, I had the same problem with my new Mogul 3.35... and it got fixed by turning on the data connection to always on. heres a reference:
http://www.sprintmogul.net/FAQ/HaizisMogulHacks.aspx
Always On Internet (Vision) Connection
- Change the "AlwaysOn" dword value from "0" to "1";
-- You may be asked for your Vision ID/PW. Just leave blank.
-- Warm Reset
[[HKEY_LOCAL_MACHINE\Comm\ConnMgr\Providers\{7C4B7A3 8-5FF7-4bc1-80F6-5DA7870BB1AA}\Connections\Sprint PCS Vision]
"AlwaysOn"=dword:00000001
"RequirePw"=dword:00000001
"ConnectionGUID"="{8956986C-8ABE-ECBF-D48F-57F7DD6A7E6A}"
"SecureLevel"=dword:00000000
"Secure"=dword:00000000
"Enabled"=dword:00000001
"EntryType"=dword:00000000
"DestId"="{F079757F-9357-4000-8305-9CA6B9B6CAEC}"
BTW, check this out;
http://www.htc.com/www/product.aspx?id=49524