Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.2; WOW64; Trident/7.0; .NET4.0C; .NET4.0E; .NET CLR 2.0.50727; .NET CLR 3.0.30729; .NET CLR 3.5.30729; Creative AutoUpdate v1.41.07; Microsoft Outlook 14.0.7188; ms-office; MSOffice 14)
In general, why do you need to forge this information? It is sent by the browser directly.
I anyway think that the UA specifies the hardware info especially for mobile devices.
Anyway there’s a website that may help you find a solution http://www.useragentstring.com/