I'm getting this exact same issue - so if anyone can help both of us out that would be great.
I have an SSIS package to consume a Web Service provided by a 3rd party. This Web Service needs a digital certificate installed to the Personal Store, I have installed this fine and can confirm everything lives where it should.
I can create a HTTP Connection through SSIS fine and can select and use the correct certificate and can test the connection successfully. Problem is when trying to create the Web Service Task. I select the HTTP connection yet when I test I get a "cannot create TLS/SSL" error which suggests it's not using the certificate.
SSIS is using a "Network Service" account and I have used the WinHttpCertCfg utility to give the service access to the certificate but still no joy. I've also ran test bypassing the Proxy and again no joy.
I must have missed something stupid here, seems a simple thing but there we go. I've ordered "The Rational Guide to Extending SSIS 2005 with Script" on the back of Jamie Thompson recommendation as it has a section on consuming web services through script - may well have to go down this route.
SQL 2005 Standard Edition (sp3). .Net Framework 3.5 sp1