Julia

There are a number of options you can use for transmitting large
amounts of binary data.  The solution you've listed (known as
base-64-encoding) is an okay solution. Your data will be transmitted
properly and it will be contained within your SOAP envelope  (meaning
that you can use things like WS-Security) if you want. It is a highly
interoperable and composable solution. The downside is that it isn't a
very efficient solution. Base 64 encoding of your binary data results
in it bloating up anywhere from 33-100% during the transmission. If you
are planning on transmitting large amounts of data quickly, then you
might potentially run into some performance and latency issues.

There are some other options out there such as DIME and SOAP with
Attachments (SwA). But both of these have issues of their own. The
solution I currently recommend people looking closely at is using
Message Transmission Optimization Mechanism (MTOM). MTOM comes with the
Web Services Enhancements 3.0 from Microsoft. It's a really easy to use
technology that avoids a lot of the pitfalls of the other options.

I've written a brief overview of the different solutions and
specifically MTOM. You can check it out at
http://peterkelcey.com/pk_blog/index.php?m=20051119

I'd also suggest checking out the following article on MSDN
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnwebsrv/html/o
paquedata.asp

Hope that helps

Peter Kelcey