If your want to do it in this manner, it just requires two registry entries and am image in png format. This referenced in page 14 of the SAP GUI 7.30 Administration Manual.
[HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\SAP\General\Appearance]
[HKEY_LOCAL_MACHINE\SOFTWARE\SAP\General\Appearance] (32 Bit OS)
"UseBrandingImage" (REG_DWORD) = 1 (activates the display of a logo in the titlebar of a SAP GUI session, if a valid path to a branding picture is provided)
"BrandingImage" (REG_SZ) with path name to picture as value data: C:\<PathToBranding>\<YourCompanyBranding>.png"
Cheers,
Dan Mead