certificates error, which is signed by CA in PI production environment

Dear All,

I am facing the certificate issue in PI production environment, while trying to communicate with third party bank web server. in development and quality we are successfully able run the interface by using the test certs(combination of public and private keys provided by bank) by importing in TrustedCas view. However, for production we generated the SCR  in PI production environment under TrustedCas view and shared with bank.

Bank has provided the below list of certificates after getting signed by the CA named SAMA.

1. Bank_CSR-27042014.crt
2. SAMA_Root_CA_DERformat_PRODUCTION.crt
3. SAMA_Shared_CA_DERformat_PRODUCTION.crt

I imported the first certificate(Bank_CSR-27042014.crt) to "Import CSR response" tab under TrustedCas view to same entry which I created while generating CSR. certificates 2 and 3 I just imported under TrustedCas view, but when I am running the interface I am getting the error as "com.sap.aii.adapter.http.api.HttpAdapterException: ERROR_SENDING_HTTP_REQUEST". I have also configured the HTTP_AAE receiver adapter to use SSL and certificates.

I have gone through many threads related to certificate, but still have below quires/clarification when it comes to utilizing the certificates signed by CA.

1. from which keys storage view shall we generate CSR and place the signed certs from CA like "TrustedCas", DEFAULT, "service_ssl", "ICM_SSL_<instance_ID>", are they different technically or they are just like a folder?
2. Exactly how many certificates we should receive from CAs to communicate with SSL enabled web server, as I have seen root ,intermediate and system, and what should be the correct order to import.
3. While configuring HTTP_AAE receiver adapter I have checked "Use SSL" and "Specify Client Certificates" as below. is it OK?

Experts please help me resolve this error or correct me if I am wrong , as this error is in production, and I do not have any certificate expert from basis team.

Thanks,

Farhan