VBA Macro to initiate sharepoint workflow

On a monthly basis I post a batch of ~20 Excel files to a sharepoint site.  I have a macro in Excel that automatically creates the files and saves them.

The next step I want to automate is to initiate a sharepoint workflow.  I have a workflow set up on sharepoint and I have to manually initiate it for each file.  I have a list of five approvers for each file.

Is it possible to use VBA to interact with a sharepoint workflow?

I am pretty good at VBA, if someone can point me to an example or even to the correct libraries or methods I can probably figure it out.

I am using Sharepoint 2010 and Excel 2010.

Thanks,

Ryan