Web Service consuming another Web Service protected by Client Cert

I apologize in advance if this is a no-brainer but I'm not that experienced as this is my first asp.net app outside a classroom. There are several threads about this error but most are incomplete and none of the answers seem to help me out. So here we go.
Web Service A (running on Windows 2008 r2, .NET4) consumes external Web Service B (protected by client cert) Error: 403 Forbridden (i can post the whole thing if necessary)
Cert is installed in Local Computer>Trusted Publishers on my server and my app's config file points to it "<clientCertificate storeLocation="LocalMachine" storeName="TrustedPublisher" x509FindType=...".
I did the trick (as stated by other threads) of dragging the client cert to the Personal store and doing "Manage Private Keys...", granting the listed apppool (in my case 'DefaultAppPool') access to the cert via "IIS apppool\DefaultAppPool"  and then dragging it back to Trusted Publi ...