Processing Banking Scenarios(Sending XML request and reciving MT940 XML ) in SAP PI 7.3

Dear Experts/Friends,

I need your valuable and immediate help on my current
banking scenario projects  which I need
to implement in SAP PI 7.3(dual stack). I will try to explain the requirement
in brief, followed by my questions.

Scenario

1- My customer xyz will be sending the payment request(extracted
by some custom RFC from ECC(FI/CO) ) to the abc bank in the form of XML
document. The output of the RFC will be the input for SAP PI 7.3 system.

2- I need to import this input in PI , moreover I need to encrypt and put the digital signature on this message
and needs to be send to bank's URL using SSL/HTTPS.

3- Bank will decrypt and  validate this XML message and will reply with
another XML message containing the SWIFT MT940 formatted data as status(eg  OK , ERROR ) of the sent message.

4- I need to receive this message in SAP PI and accordingly
I need to update the status in SAP ECC(FiCO) for each transaction

5- Bank side system is completely black box for me, only I
will get the url of the bank on which I need to post the request through
SSL/HTTPS.

XML Request (XML request to bank )

<?xml version='1.0' ?>

<PaymentInfoMessage>

<PaymentInfoRequest>

<CompanyCode>mycustomer
company code</CompanyCode>

<BankCode>BSFRSARI</BankCode>

<StartDate>2006-07-09T00:00:00</StartDate>

<EndDate>2006-07-09T00:00:00</EndDate>

<TransactionType>940</TransactionType>

</PaymentInfoRequest>

</PaymentInfoMessage>

XML Response from
bank

<?xml version="1.0"?>

<PaymentInfoMessageResponse>

  <PaymentInfoResponse>

   <TransactionType>940</TransactionType>

   <SequenceNum>1</SequenceNum>

   <ReceiptTime>2002-01-02T18:01:00</ReceiptTime>

   <ProcessStatus>1</ProcessStatus>

   <Comment>No
Comment</Comment>

   <TransactionData>:20:MT940-1007200601

:25:3210000079901

:28C:190/0001

:60F:C060709SAR12969345,17

:61:0607090709C1327200,25NTRFNONREF//NONREF

:86:TRANSFER
FROM C/A

JIZAN
BRANCH

:61:0607090709C1471681,00NTRFNONREF//NONREF

:86:TRANSFER
FROM C/A

KING
ABDUL AZIZ ST BRANCH

:61:0607090709C1657654,00NTRFNONREF//PI0010619000

:86:INCOMING
TRANSFER

HEAD
OFFICE

:61:0607090709D10000000,00NTRF2001668144//NONREF

:86:OUTGOING
TRANSFER

INTERNET
BANKING

SAR
0000010000000.00

:62F:C060709SAR7425880,42

</TransactionData>

   <CompanyCode>PARTNER01</CompanyCode>

  </PaymentInfoResponse>

  <StatusCode>OK</StatusCode>

  <StatusDetail>OK</StatusDetail>

  <ResponseItemCount>2</ResponseItemCount>

</PaymentInfoMessageResponse>

My Implementation approach

Please see the attached doc

banking scenario req.png

  I am considering this as a RFC to SOAP scenario , please
help me on my below questions.

1- is my approach is correct in consideration to the
requirement?

2- if yes, as we know in RFC to SOAP scenario the wsdl file
will be always provided by the webservice provider(in my case bank), however in
my scenario bank will provide the response only in the form of XML, so how do I
will get the wsdl file.

3- is SOAP adapter is capable to do the encryption/decryption
and digital signature, and how to post the request over SSL/HTTPS? any blog on
this for 7.3?

4- Do we need to create data type and message type for this
scenario(RFC to SOAP)?