Large XML Document causing error

Trying to read a large XML Document (greater than 80MB), but running into “OutOfMemoryError while executing trigger”. Using IS on webMethods 6.1 and using pub.file:getFile and pub.sting:bytesToString services.

There are quite a few posts around large documents handling for TN but could not find anything specific to this problem. Please let me know if there is an alternate way. I have heard that the XML file can be read on the element level but have not seen anybody doing that.

Thanks in advance.