Hi!
I´m working on a Flow that will allow me to create a new SharePoint subsite on a list´s item creation. So far I have managed to get the Flow to work using the standard team site WebTemplate (STS#0) and the project WebTemplate ids (PROJECTSITE#0).
I´m using the "Send HTTP request to SharePoint" action that looks like this:

However I want to be able to create such sites using my own custom site template which I have already created and saved as such.
Here is the question:
I need to be able to locate the correct WebTemplate ID in order to feed that information to the HTTP action, I have followed several articles including this one: https://jamesdiblasi.wordpress.com/2013/08/17/sharepoint-2013-finding-your-custom-site-template-id/ in order to do so.
By following that I was able to retrieve what I though was my site´s custom Webtemplate ID which reads:
"{662D1818-F781-416B-8474-DE74B9917DE1}#Acorde_projectTmpA"
However, when I change my Web Template from PROJECTSITE#0 to 662D1818-F781-416B-8474-DE74B9917DE1}#Acorde_projectTmpA the flow runs into an error. The output of the error shows the following:
{
"message": "Invalid file or arguments for the site template '662D1818-F781-416B-8474-DE74B9917DE1#Acorde_projectTmpA'.\r\nParameter name: WebTemplate\r\nclientRequestId: bd8074ce-8f8a-48e9-b729-37ca40aef70c\r\nserviceRequestId: a5a81f9f-3084-0000-497c-336584773c12",
"status": 400,
"errors": [
"-2147024809",
"System.ArgumentException"
]
}
Which, if I´m not mistaken, means that I´m entering a wrong value for my custom site WebTemplate. I have also tried to get this ID using PowerShell but it appears that the sites I have created using this template are not showing any WebTemplate ID:
Please guide me on where to find the custom web template ID in order to use it in my flow.
Thanks in advance.