Mortgage Property where Minors are owners along with Parents

I have booked under construction property at Ruparel Sky Greens at Kandivali West. I have kept both my 8 years twin sons as owners of the property. My property is mortgaged with ICICI HFC. At present, I leave Near S V Road, Kandivali West. I want to transfer my loan to HDFC LTD. Since Minors are owners of the property, HDFC LTD requires Permission from the court, to mortgage the share of the minor in favor of HDFC LTD. I am not sure which all documents I need to obtain to fulfill this requirement A layer suggested that we need to get an order of Guardianship from Citi Civil Court, Dindoshi. Before I proceed with Guardianship Petition and attend to the argument before Jude, I want to check if the order of Guardianship from Citi Civil Court Dindoshi would be enough for any Babk to give legal clearance in this matter.