If you are faced to 'large' Xml-documents with AIF-WebServices, you might be faced to difficulties for Inbound and OutBound services. The following two points should be applied for the client app.config, if the client uses the WCF for communicating with the AIF-WebService (Inbound-Services - you are sending large Xml-Documents to the AIF-WebService), and on the server web.config (Outbound-Services - you are receiving large Xml-documents from the WebService)
1) Changing the web.config by adding the httpRuntime Xml-element:
<httpRuntime executionTimeout="timeout in seconds" maxRequestLength="size in kilobytes" />
And choose a value for the Xml-Attribute executionTimeout that fits to the execution duration of the process.
The maxRequestLength (default value is 4096 KB) should not exceed a maximum file size of 20 MB to restrict possible denial of service attacks. Keep this value as low as possible nevertheless.
Increase the maxReceivedMessageSize (for the asmx-compatible and WS-binding) value for:
<binding name = "wsHttpWindowsAif"
maxReceivedMessageSize ="size in kilobytes">
By default this value is 4096 KB and for most Xml-documents not enough. You might have tried the MaxMessageSize as described here, but this attribute has been replaces by maxReceivedMessageSize.
If you run into performance issues running into XML processing, take a look at vtd-xml