Digitally signing xlsm file - can't get Excel to recognise certificate.

I am writing macros in excel (and word) for a small organisation. They will only ever be used internally. I want to be able to run my macros on all machines on the local area network without the various warnings popping up from Microsoft about macros being disabled, etc.

In order to retain protection, in Macro Security I want to set the macro settings to "Disable all macros except digitally signed macros", and then I want to sign the documents that I produce with a code signing certificate.

This is where the trouble begins ... we are a small not-for-profit organisation, and we are damned if we are going to pay huge amounts of money each year to one of the only three certificate vendors that Microsoft recognize - two of which are subsidiaries of Microsoft anyway (a.k.a. a greedy monopoly) - in order to get a code signing certificate.

So, my plan is this - create my own code signing certificate, export as both the public and private parts. Then sign the xlsm (and docm) files with the private key certificate and install the public key certificate on all machines in the network so that we don't get errors popping up about my macros.

All well and good, you might think. Indeed, I found the following online guide, written by someone who wanted to do what I want to do, and for much the same reason: http://www.vbforums.com/showthread.p...g-certificates

So I followed his instructions, and now I have my two files (let's call them XmisterIS.cer - the public key part and XmisterIS.pfx - the private key part).

BUT ... when I go to Tools > Digital Signature > Choose in the Visual Basic window for the project, a box pops up saying "no certificate available". So ... where do I need to (a) put the .pfx file so I can sign the document with it and (b) put the .cer file so that Excel can verify the signature?

I get the feeling that I am "close, but no cigar" ...

Microsoft have got it all rather nicely wrapped up, then ...

That would be much appreciated ... I've spent a good while looking today and put it to bed for the moment.