Unable to update my datas using MobileService

Hello,

I'm developping an app using a local SQLiteStore and MobileService on Azure. All work fine except updating data in the SQL Database on Azure.

Updating data works fine if my object model use only string and bool types. If I insert an int or datetimeoffset field, it doesn't work.
To update data, I'm using the command MobileService.SyncContext.PushAsync(); Using Fiddler, I can see that the request send is OK. I don't have any error message from the backend.

Here is an example of the used model :

public class OptionsetItem
{
    public string Id { get; set; }

    [JsonProperty(PropertyName = "optionsetName")]
    public string OptionsetName { get; set; }

    [JsonProperty(PropertyName = "value")]
    public string Value { get; set; }

    [JsonProperty(PropertyName = "pos")]
    public int Pos { get; set; }
}

If I remove the int field from my model, it works fine. If I let it, data are not updated on Azure.

Does anyone has had this kind of problem ?

Thanks for your help !!

Guillaume