xsi:nil causing data to be null when sending from flex to asp.net webservice

I am a new to ASP.NET and am attempting to create a Web Service. The problem i am running into is that when the service Soap definition comes up on the asmx page is displayed, i am getting a node with xsi:nil="true" instead of it's children. I have noticed that whenever I have a type which has a array inside this is happening.

Due to this when I am calling the web service from flex , all the arguments that are shown with xsd:nil on operation description are coming as null开发者_StackOverflow.

here is the wsdl operation description :-

http://pastebin.com/1AKrHAmn

Here is the whole wsdl of the service :-

http://pastebin.com/39wt43Wc

I am receiving null instead of arrays in images,captions and comments in the web service when I am calling the method from flex with slide as an argument.

Apparently I was doing a mistake on flex client while sending the data to web service , there was no problem on web service side