IT Process Automation

Is it possible to expose PAM processes and components for consumption via the web service?

Depending on what you are looking for you can interact with Process Instances using basic SOAP calls, or REST based Soap calls. 

You can get more details in the documentation:
SOAP API Reference

Open REST APIs

In the company where I work we have processes and other custom components and I have third party products that want to consume them.
Example:
In a process of creation of VM there are several sub-processes, among them a sub-process of network configuration. I want to expose this network subprocess in a web service so that an IBM application can evoke it by allowing you to enter the values of the input variables and having at the end the execution of the network configuration that you need.

Your IBM application can get details on the process using the REST OPEN API which allows access into the instance to get the dataset:

Perform Actions on a Process Instance

But I do not see a way to update the dataset with this method, and I am pretty sure that you will need a Form for your external application to interact with the process instance.

You respond to a form through the SOAP API:
executePendingInteraction Method

Or the better yet through the REST OPEN API:
Perform Actions on a Task

So I theorize a point where your process gets to this child process, writes information into a process level dataset,  either within this child, or possibly at the parent level prior to launching the child, and the process is paused on a User Interaction Request Form; your IBM application then reads into the process instance using the Perform Actions on a Process Instance API call to gather any relevant details, then uses the Perform Actions on a Task method to update and complete the form with the values required for the process to move forward and accomplish your network configuration.