'Someway' vs 'somehow'?

Solution 1:

I'm British. Today is the first time I have seen the word someway.

If you use Google Books Ngram Viewer, you will see that it does occur but its frequency is negligible in comparison to somehow.

The meaning appears to be the same.

Solution 2:

Somehow is short for "in some way not yet known." Someway, despite lacking formal recognition is just another way of saying the same thing. Perhaps it is even a bit clearer, eliminating the need to parse "how" as "way".

It is definitely a less established, informal word.

For Reference:

Etymonline - Somehow

somehow (adv.) 1660s, "in some way not yet known," from some + how. First attested in phrase somehow or other.

Solution 3:

Somehow is about the process itself; "in some way" (which, I suppose, is the same as "someway" - though I find that to be a fringe usage) is about the results of the process. For example, "Somehow we have to get him to change his behavior" versus "We have to get him to change his behavior in some way". The former says the method to use is unclear, while the latter says the resulting change is unclear.