Custom Attributes in VRA blueprint

[goodrz]

Hi

I am Very new to VRA. I have searched on similar topics here with no definitive answer for version VRA 8.2

I have a bluepirnt in VRA and trying to see how I can add separate dropdown in the blueprint for multiple existing Custom Attributes we have defined in Vcenter. I know there might be manyways. But I was thinking to create a custom resource and in the "lifecycle action" add the Embedded VRO worflow that already exist (called "Add custom attribute to a virtual machine"). I'll put as many as I need to equate to the number of Custom attributes we have in scope in Vcenter and populate the at blueprint deploy time just like I input everything else. 

Problem is when I try to create the lifecycle action and selecting the "Add custom attribute to a virtual machine". I get the following error. So I would be grateful if someone can explain what is wrong what and  can be done to get around this? need exact steps please as I am very novice 🙂

"The currently selected create workflow does not return a single instance of an SDK object type. Please select a workflow which has at least one singular (no 'Array/' prefix) SDK object type output parameter."

[frippeisking]

It's very common with these 0 relies threads on this forum. I wonder what the adoption rate is for vRA/vRO now adays.
I too am stuck with this error. Made a simple workflow that returns a string which I guess is not of the type "SDK object". 

[frippeisking]

Use vRealize Orchestrator to create custom resources

Each custom resource is based on a vRealize Orchestrator SDK inventory type and is created by a vRealize Orchestrator workflow that has an output which is an instance of your desired SDK type. Primitive types, such as Properties, Date, string, and number are not supported for the creation of custom resources.