After much searching around, I’ve finally managed to sign and trust my ActiveX control (written in VB6). For my own sanity, I’m posting here the summary of how to do it (and maybe someone else may find it of use one day!).
Marking the ActiveX control as ‘Safe’
Firstly the ActiveX control must be declared to run in a safe mannor. There are a couple of ways to accomplish this, but the easiest method is:
Digitally Signing the ActiveX Control
Use the pvk2pfx.exe utility from Microsoft, provided as part of Microsoft Visual Studio (I’m using vn 2008):
pvk2pfx.exe -pvk mykey.pvk -spc mycert.sfc -pfx OutputPFX.pfx
(where the .pvf and .sfc files are provided by the certificate authority).
This generates the .pfx file that can be used with the signtool.exe that comes with Microsoft Visual Studio:
signtool.exe sign /f OutputPFX.pfx /v ActiveX.ocx
Link to Microsoft Article: http://msdn.microsoft.com/en-us/library/ee416211%28VS.85%29.aspx