Esteban,
I suggest you use the Object Model API which allows you to develop SSIS packages programmatically. Using that, you can make use of any .net code that allows you to gather data/metadata from text files. Also, the assumption is that, since you are using SSIS, you already might be familiar with writing code in C#/VB.Net
Now, if you are just starting with the Object Model API, there would be a huge learning curve (but it is worth learning it if SSIS is your day to day life). If you do not have the time to invest right now, I would recommend you to use a library I wrote (called Pegasus) which greatly simplifies how you can use the Object Model API; you can create your packages in an almost declarative fashion (using C#).
On Github, there is an example that shows how to create a package that loads any number of text files with differing schemas in a given folder. See here; specifically the method GenerateProjectToLoadTextFilesToSqlServerDatabase().
In the example, I use a third party .Net library called lumenworks.framework to probe delimited files and get their metadata. Using this library, I get the names of the columns; and I also infer data types and lengths based on sampling the first 'n' number of rows. (In my code, I am only inferring ints, dates and strings; if you have more data types, add relevant code accordingly). Or you can specify one specific data type and length (looks like you want to use string of 500 chars) for all your columns. [Or (in some cases), you might have this metadata available outside in a excel file/config file.] Then I use this metadata to configure my text file connection managers programmatically.
YOu can download the code from Github and run the DataFlowExample by specifying where your source files are and see how far it gets you.
Another recommendation would be Biml, but I am not sure if you can incorporate your own/third party full fledged C# code (not just snippets) into Biml workflow. If you can, then go with Biml.
Let me know if you have any questions.
Suggest type
in connection manager doesn't help ? – Hypostyle