Suggest me way for calling Function Module in BSP page

Question

Dear Friends,
I want to create sales order using BSP. For that there is an bapi called BAPI_SALES_CREATEFROMDAT2. I have two ways to do that.
1. I will create all the required structure on the BW system and then i can call the bapi.
2. I will create another function module which calls the BAPI_SALES_CREATEFROMDAT2. and i will pass all the require parameters to my created Function module.
In the first case i suppose to create structure for header data, order items and partner data. It is quite lenghty work.
In the second case i need not to create any kind of structure or types-pool.
If answer is case1 then should i create exact structure or i can create that many fields contained structure which i require?
Suggest me that whether should i follow first case or i should follow second case and also which one is more powerful?

Answer 1

Thanks for giving me answer.
I have tried to find through BAPI Browser for BAPI_SALESORDER_CREATEFROMDAT2 but unfortunately it is not creating the structure. This is very suprising for me because as per your weblog and as per your answer it should be generated. Now i have two choices :
1. I create same structure on 6.20 system manually for that i have to create around 100 data elements or may be more than that which are not exits on 6.20 system.
2. I will create another function module on 4.6c system which calls BAPI_SALESORDER_CREATEFROMDAT2 and i need to pass only selected parameters.
2nd option is suitable for me but i have doubt that is the proper way for working production?