Mass transfer of big files from sap to external

Hi experts,

Any ideas on how to transfer a number of files which are big like 10 mb, 20 mb so on during business hours to non sap system - Salesforce.

I have tried to send the data in an idoc, but it is taking up resources at pi and slowing down other interface. Also taking huge time.

FTP is last option as other system - Salesforce doesn't have FTP functionality.

Right now we are sending the data in a soap XML message.

Please let me know if there are any other ways.