I managed to create a product via the XMLRPC in Odoo 9, however i have hard time to set a price within the pricelist tab.

Did lot of searching for the many2many situation, but still not luck. 

public interface IOdooCommon : IXmlRpcProxy 
   {        [XmlRpcMethod("login")]
        int Login(string database, string username, string password);
    }

    public interface IOdooObject : IXmlRpcProxy 
   { 
       [XmlRpcMethod("execute")]
        int Create(string dbname, int uid, string pwd, string obj, string method, XmlRpcStruct strct);
 
       [XmlRpcMethod("execute")] 
       XmlRpcStruct[] Read(string dbname, int uid, string pwd, string obj, string method, int[] ids, string[] fields);

        [XmlRpcMethod("execute")] 
       int[] Search(string dbname, int uid, string pwd, string obj, string method, object[] filter);

        [XmlRpcMethod("execute")] 
       bool Unlink(string dbname, int uid, string pwd, string obj, string method, int[] ids);

        [XmlRpcMethod("execute")]
        bool Write(string dbname, int uid, string pwd, string obj, string method, int[] ids, XmlRpcStruct strct);
 
 }
private void button1_Click(object sender, EventArgs e)
        {
            string dbname = "database"; 
            string userName = "contact@ttest.ro"; 
            string pwd = "passw";
            IOdooCommon odooProxyCommon = XmlRpcProxyGen.Create<IOdooCommon>();
            odooProxyCommon.Url = "http://192.168.0.105:8069/xmlrpc/common";
            int userId = odooProxyCommon.Login(dbname, userName, pwd);
            IOdooObject odooProxyObject = XmlRpcProxyGen.Create<IOdooObject>();
 
            XmlRpcStruct dic = new XmlRpcStruct();
 
           dic.Add("name", textBox1.Text);
 
           XmlRpcStruct pret = new XmlRpcStruct(); 
           pret.Add("pricelist_id", 2);
           pret.Add("fixed_price", 100);
 
           dic.Add("item_ids", pret);
     
 
           int pretX = odooProxyObject.Create(dbname, userId, pwd, "product.product", "create", dic);
}