The executeAsync method you're referring to only accepts IMendixObject or IMendixIdentifier parameters for microflows (see the method documentation).
As a workaround you could call this method for a Java Action (for a Java Action other parameter types are accepted) and in this Java Action execute the microflow synchronously.
I think it's a good idea to add an executeAsync variant to the Core class which does accept other parameter types, could you perhaps file a ticket for this?
Is probably running, but it is not able to interact with the user-interface. Change you check for changed data in the database?
The signature of Core.execute is
(IContext context, String action, Map<String,Object> args)
however, the signature of Core.executeASync is
(IContext context, String action, Object... args)
So probably you should call your action like (never used Async from java)
Core.executeAsync(this.getContext(), this.MicroFlowName, new Long(CombinedNumber));
Core.executeAsync(this.getContext(), this.MicroFlowName, "Combined", new Long(CombinedNumber));
When I run the code with execute, in debug my parameter shows up:
But, when I try all the permutations of the Async's signature, the Microflow is started without the parameter:
So, how would you run 2 web services simultaneously from a microflow? I'm trying Java code in a Java Action, but I'm sure somebody had to do something like this before in Mendix?