Swashbuckle Swagger url from http to https .NET - asp.net-mvc

Question

My API is an HTTP API (not HTTPS) developped in ASP.NET.
Nevertheless, when deployed in the DMZ, there is something, somewhere on the network, not under my responsability, that only accept HTTPS and act as a reverse proxy to my HTTP API.
This leads to the swagger UI misbahaving.
The URL to access the swagger UI is "https://external_public_name/api/swagger/ui/index#/" but he one in the text field in the green ribbon is "http://external_public_name/api/swagger/docs/v1".
Therefore, the page is blank, with the error at the console
Mixed Content: The page at
'https://external_public_name/api/swagger/ui/index' was loaded over
HTTPS, but requested an insecure XMLHttpRequest endpoint
'http://external_public_name/api/swagger/docs/v1'. This request has
been blocked; the content must be served over HTTPS.
Replacing, manually the URL in the textbox with HTTPS is working fine.
Where should I change something to update that URL (maybe at runtime)?
P.S.: I already had to rewrite the SwaggerConfig.cs as SwaggerConfig.vb to be able to use it.
Imports System.IO
Imports System.Reflection
Imports System.Web.Http
Imports System.Web.Http.Description
Imports Swashbuckle.Application
Imports Swashbuckle.Swagger
<Assembly: PreApplicationStartMethod(GetType(SwaggerConfig), "Register")>
Public Class SwaggerConfig
Public Class KnownSubTypesDocumentFilter
Implements IDocumentFilter
Public Sub Apply(swaggerDoc As SwaggerDocument, schemaRegistry As SchemaRegistry, apiExplorer As IApiExplorer) Implements IDocumentFilter.Apply
schemaRegistry.GetOrRegister(GetType(BookController.BookList))
End Sub
End Class
Public Shared Sub Register()
Dim thisAssembly = GetType(SwaggerConfig).Assembly
GlobalConfiguration.Configuration.EnableSwagger(
Function(c)
c.Schemes({"https"})
c.SingleApiVersion("v1", "api")
c.DocumentFilter(Of KnownSubTypesDocumentFilter)()
Return c
End Function).EnableSwaggerUi(
Function(ui)
ui.DocumentTitle("Skippy's API")
ui.DocExpansion(DocExpansion.List)
ui.SupportedSubmitMethods()
Return ui
End Function)
End Sub
End Class